Trees, shrubs, annual or perennial herbs, subshrubs, vines, or lianas, infrequently monocaulous or creeping and rooting at nodes, terrestrial or infrequently epiphytic, with bisexual flowers, infrequently dioecious, or rarely polygamo-dioecious (Diplospora, Galium, Guettarda, perhaps Brachytome) or monoecious (Galium), evergreen or sometimes deciduous (Hymenodictyon), sometimes armed with straight to curved spines (formed by modified stems or peduncles), infrequently with elongated principal stems bearing lateral short shoots (i.e., brachyblasts; Benkara, Catunaregam, Ceriscoides, Himalrandia, Leptodermis, Serissa), infrequently with lateral branches or short shoots spinescent (i.e., prolonged, sharp, and leafless at apex), infrequently with reduced internodes that give an appearance of verticillate leaf arrangement (Brachytome, Damnacanthus, Duperrea, Rothmannia, Rubovietnamia), infrequently with buds resinous (Gardenia) or mucilaginous (Scyphiphora), infrequently with tissues fetid when bruised, [rarely with swollen hollow stems or leaf bases housing ants (Neonauclea)]; branchlets terete to angled or quadrate, in latter two cases often becoming terete with age, or rarely flattened (Wendlandia) or winged (Hedyotis, Rubia), buds conical or rounded with stipules valvate or imbricate, or infrequently flattened with stipules erect and pressed together (Cinchona, Haldina, Nauclea, Neonauclea). Raphides present or absent. Leaves opposite, verticillate, or apparently verticillate (i.e., closely set due to reduced internodes), decussate or occasionally distichous, petiolate to sessile, infrequently somewhat to strongly anisophyllous, rarely punctate- or striate-glandular (Galium); margins flat to occasionally undulate or crisped, entire or rarely lobed (Hymenodictyon, Morinda) to denticulate or serrate (Hymenodictyon, Leptomischus, Ophiorrhiza, Wendlandia); secondary veins pinnate or rarely triplinerved or palmate (Hedyotis, Rubia), free (i.e., eucamptodromous) or uniting near margins (i.e., brochidodromous) in weak to well-developed or rarely substraight submarginal vein, sometimes with foveolate (i.e., pitted or cryptlike) and/or tufted (i.e., pubescent) domatia (i.e., structures that house mites) in abaxial axils, these rarely also present in axils of tertiary veins (Morinda), with presence of domatia often variable within a species; tertiary and/or quaternary venation rarely arranged in regular squares (Guettarda), regular rectangles (i.e., clathrate; Urophyllum), or lineolate (i.e., closely parallel within each areole; Timonius); petiole rarely articulate at base (Ixora); stipules persistent with leaves, deciduous before leaves, or quickly caducous, interpetiolar and infrequently fused to adjacent petioles or leaf bases, sometimes united around stem into a sheath, rarely completely united into a conical cap (i.e., calyptrate; Gardenia), with interpetiolar portion variously triangular in general shape to truncate, with apex entire or bilobed, multifid, lacerate, setose, or laterally appendaged, with apex, lobes, setae, and/or appendages sometimes glandular (Chassalia, Hedyotis, Hymenodictyon, Knoxia, Mitchella, Mycetia, Neanotis, Ophiorrhiza, Pentas, Pseudopyxis, Psychotria, Trailliaedoxa), internally (i.e., adaxially) with small to well-developed colleters (i.e., glandular trichomes), these infrequently persistent after stipules fall (Psychotria), or stipules rarely expanded into 1 to several leaflike segments and then apparently absent due to leaflike form that gives an appearance of verticillate leaves (Argostemma, Asperula, Galium< Fls perfect, mostly 4(–8)-merous, epigynous, sympetalous, regular; cal mostly small, with open aestivation, or obsolete; stamens on the cor-tube, as many as and alternate with the lobes; ovary inferior, mostly 2(–5)-carpellate and plurilocular, with axile (or axile-basal or axile-apical) placentation; style slender, terminal, with lobed or capitate stigma, or (as in Galium) the styles distinct; ovules and seeds 1–many per locule; seeds with a dicotyledonous, usually straight embryo embedded in the oily endosperm; herbs or more often woody plants with simple, mostly entire, commonly decussately opposite lvs and interpetiolar (usually connate) stipules, or with whorled lvs and no stipules, the stipules typically bearing colleters within, or seldom the stipules reduced to mere interpetiolar lines; infls basically cymose. 450/6500, cosmop. but mostly trop. and subtrop. Trees, shrubs or rarely herbs Leaves opposite or rarely verticillate, entire; stipules inter- or intra-petiolar, often connate, rarely leafy and not distinguishable from the leaves Seeds rarely winged, mostly with endosperm, the latter rarely ruminate; embryo straight or curved Ovary inferior or rarely superior, 2- or more-celled, with axile, apical or basal placentas, or rarely 1-celled with parietal placentas; style often slender; ovules 1 to many Fruit a capsule, berry or drupe Corolla epigynous, more or less tubular, rarely campanulate; lobes 4-12, contorted, imbricate or valvate Stamens epipetalous, as many as and alternate with the corolla-lobes; anthers mostly separate, 2-celled, opening lengthwise or rarely by terminal pores, rarely transversely septate Flowers usually hermaphrodite, actinomorphic or very rarely slightly zygomorphic, solitary to capitate Calyx adnate to the ovary Flowers rarely solitary, mostly in various terminal or axillary inflorescences, all basically cymose but variously aggregated into panicles, etc., occasionally in globose heads to an extent that the ovaries are adnate; bracts vestigial to well developed, even conspicuous; flowers usually hermaphrodite, rarely unisexual, regular or nearly so (except in >i>Posoqueria (America)) or corolla-tube rarely curved, homostylous or quite often heterostylous with 2 or rarely 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous)) Calyx gamosepalous, the tube mostly adnate to the ovary, (3–)4–5(–8)-toothed or -lobed, sometimes only minutely so, with open, valvate, imbricate or contorted aestivation, 1 or several lobes sometimes slightly to very considerably enlarged to form a leafy often coloured lamina Small to large trees, shrubs or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; tissues in many tribes containing abundant rhaphides Leaves opposite or verticillate, decussate, almost always entire, very rarely (not in East Africa) palmatifid, toothed or finely denticulate, always obviously stipulate (save in some Rubieae, where the stipules may be considered foliar or almost absent according to interpretation), the stipules interpetiolar or intrapetiolar, entire or, particularly in herbaceous genera, variously divided into lobes or fimbrieae, often tipped or separated by mucilaginous hairs known as colleters and often with colleters inside the base; the leaves in certain tribes sometimes contain small bacterial nodules Corolla small to large and showy, gamopetalous, rotate to salver-shaped or funnel-shaped, the tube often very long, (3–)4–5(–11)-lobed, the lobes mostly contorted or valvate, sometimes valvate-induplicate, rarely imbricate or quincuncial Stamens usually as many as the corolla-lobes and alternate with them, epipetalous; anthers basi- or dorsifixed, introrse, the thecae rarely multilocellate transversely Pollen various, mostly simple, isopolar and 3-colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some >i>Gardenieae) in tetrads or rarely in polyads Disc often present, 2-lobed or tubular Ovary inferior, rarely half-inferior or (in >i>Gaertnera) superior, syncarpous of 2–5 or more carpels, but predominantly of 2 and therefore predominantly 2-locular, but 3–5 or even 12 or more (e.g. in >i>Urophylleae due to supplementary incomplete partitions); placentation axile or (in some >i>Gardenieae) parietal; ovules 1–many per locule, often embedded in fleshy placentas, erect, basal or horizontal, anatropous; style simple, usually long and narrow, the “stigma” either cylindrical, clavate, or otherwise modified to form a “receptaculum pollinis” or divided into 2–many linear, spathulate or clavate lobes, the actual stigmatic surface sometimes confined to certain areas, e.g. the inner faces of the lobes Fruit small to quite large (0.2–20 cm.), a capsule, berry or drupe or indehiscent or woody, occasionally (e.g. in >i>Nauclea and >i>Morinda) united to form syncarps, (1–)2–many-seeded, if capsules then loculicidal or septicidal or opening by a beak Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; albumen present (save in >i>Guettardeae); embryo straight or rarely curved, the radicle mostly longer than the cotyledons Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; endosperm present (save in Guettardeae), entire or ruminate; embryo straight or rarely curved; radicle erect or horizontal, mostly longer than the cotyledons, orientation pendulous Fruit small to very large, 2–many-seeded, dehiscent (capsules either loculicidal, septicidal, opening by a beak or infrequently circumscissile, or splitting into mericarps), or indehiscent (berries, including forms with woody walls, or drupes), occasionally (eg in Nauclea and Morinda) united to form syncarps; if drupes containing one-seeded pyrenes thin- or thick-walled, opening by pre-formed germination slits or not, or less often a multi-seeded stone Ovary inferior, rarely half-inferior or superior (in Gaertnera), syncarpous of 2–10(12 or more) carpels, but predominantly of 2, and therefore predominantly 2-locular, but 3–10(12) (in Urophylleae can appear higher than actual carpel number due to supplementary incomplete partitions), or infrequently uni-locular (or partly so); ovules l–numerous per locule; placentation axile (attached to septum at apex, middle or base, usually on a placenta, often embedded in fleshy placentas) or infrequently (in some Gardenieae) parietal; ovules anatropous; style simple, usually long (but very short in Rubieae) and narrow, at the top either cylindrical, clavate, or otherwise modified to form a pollen presenter (the actual stigmatic surface sometimes confined to specific areas, eg the inner faces of the lobes**), or divided into 2–many (according to number of carpels) linear, spathulate or clavate stigmatic lobes Disk usually functioning as a nectary, positioned above the ovary inside the base of the calyx limb, annular to cushion-shaped or tubular, sometimes 2-lobed, occasionally fused to base of calyx limb-tube (Naucleeae) or absent (in wind-pollinated flowers) Pollen various, mostly simple, isopolar and 3- colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely in polyads Stamens usually as many as the corolla lobes and alternate with them, epipetalous or not (some New World tribes only); anthers basi- or more often dorsifixed, introrse rarely porate (not in the Flora Zambesiaca area), the thecae rarely transversely multilocellate Corolla predominantly white but sometimes coloured, small to large and showy, gamopetalous, mostly salver- shaped to funnel-shaped or less often campanulate, occasionally tube very short, the tube rarely curved, (3)4–5(11)-lobed, the lobes contorted (mostly to the left, infrequently to the right) or valvate (sometimes induplicate or reduplicate), with or without a contact zone (i.e. thickened margin), less often imbricate (tab. 73/B–D) Calyx gamosepalous, the tube (i.e. calyx tube**) mostly adnate to the ovary, the limb with tubular part (i.e. limb-tube) present or absent, truncate or bearing minute teeth to well developed lobes (tab. 73/A1–A4), valvate (often separated by sinuses), or less often imbricate or contorted in aestivation, in a few genera 1–several lobes sometimes slightly to considerably enlarged to form a leaf-like often coloured blade (calycophyll) (tab. 73/A5) Stipules interpetiolar or occasionally intrapetiolar (mostly New World taxa); lobes shortly fused above the petioles and sometimes forming a sheath, or lobes free, entire, bifid or rarely laciniate, or particularly in herbaceous genera, fimbriate, often tipped with or separated by colleters (mucilaginous glands) (tab. 74), often with colleters inside the limb, especially towards the base Inflorescences terminal or axillary, basically thyrsoid, variously aggregated into panicles etc., occasionally in globose heads sometimes to an extent that the ovaries are adnate, or sometimes flowers solitary; bracts vestigial to well developed, even conspicuous Flowers regular or slightly to distinctly (not in Africa) zygomorphic, hermaphrodite or less often unisexual, homostylous, in which case very often protandrous, with or without pollen presentation (tab. 73/F,G), or rarely protogynous (not in Africa), or heterostylous with 2 or less often 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous) (tab. 73/E) Small to large trees, shrubs (including suffrutices from woody rootstocks) or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; raphides (tab. 1/7) present or absent; crystal sand absent or present (these two mutually exclusive) Leaves opposite or occasionally verticillate, decussate, almost always entire, very rarely sparsely toothed or lobed (not in the Flora Zambesiaca area), always obviously stipulate (save in some Rubieae, where the stipules may be considered leaf-like or almost absent according to interpretation); domatia (mite associated pits or tufts of hairs) very often present axils of lateral nerves on the leaf lower surface; bacterial nodules present in a few genera Flowers regular or slightly to distinctly (not in Africa) zygomorphic, hermaphrodite or less often unisexual, homostylous, in which case very often protandrous, with or without pollen presentation (tab. 73/F,G), or rarely protogynous (not in Africa), or heterostylous with 2 or less often 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous) (tab. 73/E) Corolla predominantly white but sometimes coloured, small to large and showy, gamopetalous, mostly salver- shaped to funnel-shaped or less often campanulate, occasionally tube very short, the tube rarely curved, (3)4–5(11)-lobed, the lobes contorted (mostly to the left, infrequently to the right) or valvate (sometimes induplicate or reduplicate), with or without a contact zone (i.e. thickened margin), less often imbricate (tab. 73/B–D) Calyx gamosepalous, the tube (i.e. calyx tube**) mostly adnate to the ovary, the limb with tubular part (i.e. limb-tube) present or absent, truncate or bearing minute teeth to well developed lobes (tab. 73/A1–A4), valvate (often separated by sinuses), or less often imbricate or contorted in aestivation, in a few genera 1–several lobes sometimes slightly to considerably enlarged to form a leaf-like often coloured blade (calycophyll) (tab. 73/A5) Pollen various, mostly simple, isopolar and 3- colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely in polyads Stamens usually as many as the corolla lobes and alternate with them, epipetalous or not (some New World tribes only); anthers basi- or more often dorsifixed, introrse rarely porate (not in the Flora Zambesiaca area), the thecae rarely transversely multilocellate Ovary inferior, rarely half-inferior or superior (in Gaertnera), syncarpous of 2–10(12 or more) carpels, but predominantly of 2, and therefore predominantly 2-locular, but 3–10(12) (in Urophylleae can appear higher than actual carpel number due to supplementary incomplete partitions), or infrequently uni-locular (or partly so); ovules l–numerous per locule; placentation axile (attached to septum at apex, middle or base, usually on a placenta, often embedded in fleshy placentas) or infrequently (in some Gardenieae) parietal; ovules anatropous; style simple, usually long (but very short in Rubieae) and narrow, at the top either cylindrical, clavate, or otherwise modified to form a pollen presenter (the actual stigmatic surface sometimes confined to specific areas, eg the inner faces of the lobes**), or divided into 2–many (according to number of carpels) linear, spathulate or clavate stigmatic lobes Disk usually functioning as a nectary, positioned above the ovary inside the base of the calyx limb, annular to cushion-shaped or tubular, sometimes 2-lobed, occasionally fused to base of calyx limb-tube (Naucleeae) or absent (in wind-pollinated flowers) Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; endosperm present (save in Guettardeae), entire or ruminate; embryo straight or rarely curved; radicle erect or horizontal, mostly longer than the cotyledons, orientation pendulous Fruit small to very large, 2–many-seeded, dehiscent (capsules either loculicidal, septicidal, opening by a beak or infrequently circumscissile, or splitting into mericarps), or indehiscent (berries, including forms with woody walls, or drupes), occasionally (eg in Nauclea and Morinda) united to form syncarps; if drupes containing one-seeded pyrenes thin- or thick-walled, opening by pre-formed germination slits or not, or less often a multi-seeded stone Stipules interpetiolar or occasionally intrapetiolar (mostly New World taxa); lobes shortly fused above the petioles and sometimes forming a sheath, or lobes free, entire, bifid or rarely laciniate, or particularly in herbaceous genera, fimbriate, often tipped with or separated by colleters (mucilaginous glands) (tab. 74), often with colleters inside the limb, especially towards the base Inflorescences terminal or axillary, basically thyrsoid, variously aggregated into panicles etc., occasionally in globose heads sometimes to an extent that the ovaries are adnate, or sometimes flowers solitary; bracts vestigial to well developed, even conspicuous Small to large trees, shrubs or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; tissues in many tribes containing abundant rhaphides Leaves opposite or verticillate, decussate, almost always entire, very rarely (not in Africa) palmatifid, toothed or finely denticulate, always obviously stipulate (save in some Rubieae, where the stipules may be considered foliar or almost absent according to interpretation), the stipules interpetiolar or intrapetiolar, entire or, particularly in herbaceous genera, variously divided into lobes or fimbriae, often tipped or separated by mucilaginous hairs known as colleters and often with colleters inside the base; the leaves in certain tribes sometimes contain small bacterial nodules Corolla small to large and showy, gamopetalous, rotate to salver-shaped or funnel-shaped, the tube often very long, (3)4–5(11)-lobed, the lobes mostly contorted or valvate, sometimes valvate-induplicate, rarely imbricate or quincuncial Calyx gamosepalous, the tube mostly adnate to the ovary, (3)4–5(8)-toothed or lobed, sometimes only minutely so, with open, valvate, imbricate or contorted aestivation, 1 or several lobes sometimes slightly to very considerably enlarged to form a leafy often coloured lamina Flowers rarely solitary, mostly in various terminal or axillary inflorescences, all basically cymose but variously aggregated into panicles, etc., occasionally in globose heads to an extent that the ovaries are adnate; bracts vestigial to well developed, even conspicuous; flowers usually hermaphrodite, rarely unisexual, regular or nearly so (except in Posoqueria (America)) or corolla tube rarely curved, homostylous or quite often heterostylous with 2 or rarely 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous)) Ovary inferior, rarely half-inferior or (in Gaertnera) superior, syncarpous of 2–5 or more carpels, but predominantly of 2 and therefore predominantly 2-locular, but 3–5 or even 12 or more (eg in Urophylleae due to supplementary incomplete partitions); placentation axile or (in some Gardenieae) parietal; ovules 1-many per locule, often embedded in fleshy placentas, erect, basal or horizontal, anatropous; style simple, usually long and narrow, the “stigma” either cylindrical, clavate, or otherwise modified to form a “receptaculum pollinis” or divided into 2-many linear, spathulate or clavate lobes, the actual stigmatic surface sometimes confined to certain areas, eg the inner faces of the lobes Disc often present, 2-lobed or tubular Pollen various, mostly simple, isopolar and 3-colporate, but sometimes porate, the number of colpi or pores varying from 2–25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely polyads Stamens usually as many as the corolla-lobes and alternate with them, epipetalous; anthers basi-or dorsifixed, introrse, the thecae rarely multilocellate transversely Leaves opposite or occasionally verticillate, decussate, almost always entire, very rarely sparsely toothed or lobed (not in the Flora Zambesiaca area), always obviously stipulate (save in some Rubieae, where the stipules may be considered leaf-like or almost absent according to interpretation); domatia (mite associated pits or tufts of hairs) very often present axils of lateral nerves on the leaf lower surface; bacterial nodules present in a few genera Small to large trees, shrubs (including suffrutices from woody rootstocks) or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; raphides (tab. 1/7) present or absent; crystal sand absent or present (these two mutually exclusive) Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; albumen present (save in Guettardeae); embryo straight or rarely curved, the radicle mostly longer than the cotyledons Fruit small to quite large (0|2–20 cm.), a capsule, berry or drupe or indehiscent or woody, occasionally (eg in Naulea and Morinda) united to form syncarps, (1)2-many-seeded, if capsules then loculicidal or septicidal or opening by a beak ENTRENOEUDS, EPINES ET CROCHETS Les entrenoeuds cylindriques ou quadrangulaires sont parfois modifiés par des myrmécodomaties ou cavités médullaires habitées par des fourmis (Rothmannia, Cuviera, Canthium, Vangueriopsis, Nauclea, Heinsia). Les noeuds ou même les entrenoeuds peuvent émettre des racines adventives, soit au niveau du sol (lianes rampantes), soit dans un terreau epiphyte souvent retenu par les stipules. Il n'y a jamais de vrilles, mais parfois des épines (Xeromphis, Gardenia, Didymosalpynx, Cuviera, Canthium, Vangueria, Plec-troniella, Rutidea) ou des crochets (Uncaria). FEUILLES, STIPULES ET GLANDES SOUS-STIPULAIRES Les feuilles sont simples et entières (le remarquable et très archaïque genre Pentagonia d'Amérique fait exception), opposées décussées, jamais subopposées, parfois verticillées (Fadogia, Temnocalyx, Adina, Pausinystalia, Schumanniophyton). Les feuilles sont parfois inégales dans une même paire (anisophyllie): des réductions unilatérales très fortes ou même totales s'observent dans le genre Pseudosabicea. Le limbe n'est jamais denté mais la marge est finement denticulée chez certains Lasianthus. La nervation du limbe est de type penné. Des domaties foliaires sont fréquentes aux aisselles de certaines nervures dans de nombreux genres; elles ne sont pas absolument constantes chez toutes les espèces d'un même genre ni dans toutes le populations d'une même espèce. Des galles d'origine bactérienne se rencontrent dans certains genres (Pavetta, Tricalysia, Psychotria). Les bactéries qu'elles contiennent sont totalement intégrées à la plante; elle sont présentes dans la graine et se perpétuent d'une génération à l'autre à travers la reproduction sexuée. Ces galles présentent des formes spécifiques et sont d'un grand intérêt pour la systématique. Le pétiole est rarement nul et présente le plus souvent un canal adaxial; les bords du canal qui sont en continuité avec les marges du limbe, sont en outre parfois connées aux stipules (Hédyotidées). Les stipules interpétiolaires sont toujours présentes, réduites ou développées, parfois caduques, uni, bi ou multidentées, parfois soudées en ochréa à l'intérieur des pétioles (Gardenia, Gaertnera, Bertiera). Les stipules, de même que les lobes calycinaux, présentent toujours vers leur base, en position interne ou latérale, des organes glandulaires qui secrètent des cérides; ces cérocystes sont généralement accompagnés de poils épidermiques. Devenus inutiles après le développement des organes qu'ils accompagnent, les cérocystes subsistent sous forme de petits denticules aigus noirs ou brunâtres. II n'existe pas de latex chez les Rubiaceae, mais les plaies peuvent exsuder certaines gommes. OXALATE DE CALCIUM L'oxalate de calcium est extrêmement fréquent, sinon même constant chez les Rubiaceae. Il se présente sous des formes cristallisées variables telles que macles, oursins ou raphides. Les raphides semblent prédominer chez les Rubiaceae herbacées (Hédyotidées, Spermacocées, Rubiées), mais des arbustes et des arbrisseaux en sont aussi pourvus (Psychotriées, Morindées, Urophyllées, Cratérispermées). La constance des raphides au niveau des tribus citées et de quelques autres a été retenue par certains auteurs pour distinguer une sous-famille des Rubioïdées, pourvue de raphides, d'une sous-famille des Cinchonoïdées dans laquelle l'oxalate n'est connu que sous forme de macles ou d'orsins (tribus des Naucléées, Cinchonées, Mussaendées, Gardéniées; Ixorées, Vanguériées etc.) Malgré l'opinion de Verdcourt ( Bull. J. R. Brux. 28 1958 ), cette division de base n'a pas été suivie, dans la présente flore. INFLORESCENCES Les inflorescences sont de types variés, terminales, subterminales ou axillaires; elles peuvent être uni, pauci ou multiflores et se présenter en cymes, panicules, grappes (généralement composées de cymes contractées, très rarement simples par appauvrissement des cymes latérales comme chez Bertiera Chevalieri), glo-mérules ou capitules; ces derniers sphériques ou non, syncarpiques ou non, avec ou sans involucre. La cauliflorie est assez rare (Slelecantha cauliflora, Ecpoma geanthum). Les bractées florales sont recaulescentes ou non, vestigielles ou protectrices (Mitragyna rubrostipulâta, Cuviera Letestui), attractives ou non. Les bractées sont parfois absentes à certaines ramifications inflorescentielles (quelques Sabicea) ou entre les fleurs de certains capitules (Burtt-davya, Breonia). L'involucre de certaines espèces est formé de pièces libres ou soudées entre elles; il se développe habituellement à partir des préfeuilles portées par le pédoncule de l'inflorescence (Sabicea, Stipularia, Cephaelis). FLEURS, PERIANTHE ET ANDROCEE Les fleurs sont hermaphrodites, très rarement unisexuées ou polygames. Elles peuvent être toutes semblables (isostylie) ou de deux types différents (hétérostylie): les fleurs à filets staminaux longs et à style court sont dites brévistyles; les fleurs à filets staminaux courts et à style long sont dites longistyles. Ces deux types floraux se présentent toujours sur des pieds différents, et la fécondation ne peut s'effectuer que par pollinisation croisée entre ces deux types de pieds. Le réceptacle est enveloppant et soudé à l'ovaire, d'où la position infère de ce dernier par rapport au périanthe. Calice gamosépale à (3)4-5(8) lobes d'aspect variable, égaux ou non, parfois très réduits à nuls, ou au contraire plus ou moins foliacés, imbriqués, contortés ou espacés. Un ou plusieurs sépales foliacés peuvent avoir un développement important et jouer un rôle attractif par leur couleur voyante (Mussaendées, plusieurs genres). Corolle gamopétale actinomorphe, très rarement ± zygo-morphe (Posoqueria en Amérique), parfois à tube i coudé (Chas-salia) ou courbé. Nombre de lobes de 3 à 10, ordinairement 4-5; préfloraison souvent contortée ou valvaire, parfois valvaire indupliquée, plus rarement quinconciale. Les lobes ou pétales sont ± réfléchis ou courbés extérieurement à l'anthèse, étalés ou parfois érigés. Le tube peut être long (jusqu'à 20 cm chez certaines Gardéniées)ou ± court, charnu ou non. Pilosité interne variable, parfois discontinue en zones annulaires ou en bandes verticales; poils ± abondants, ± fins, dressés ou rabattus, parfois fournis et saillants au dessus de la gorge. Les étamines sont en même nombre que les pétales; les filets sont soudés entre ces derniers. Les anthères sont situées à une hauteur variable, soit incluses, à un niveau ± bas dans le tube, soit exsertes, avec des filets de longueur très variable. L'anthère est introrse, basi ou dorsifixe, ± oblongue, parfois sagittée, à 2 loges bilocellées longitudinalement, rarement multilocellées tranversalement (Dictyandra et, en Amérique, Isertia). Sous l'insertion des filets et dans la partie étroite du tube, on rencontre dans certains genres, des fentes en boutonnières interpétalaires accompagnées, sur une petite longueur, d'un décollement des filets eux-mêmes. POLLEN Dans le cas général, le pollen se présente en grains simples isopolaires à 3 apertures de type colporus (sillons longitudinaux n'atteignant pas les pôles, avec un pore médian). Diverses exceptions sont à signaler: Sillons sans pores apparents: Rubia, Borreria. Pores sans sillons: Vanguériées, Psychotriées, Craterispermum, Mussaenda, Stipularia. Apertures nombreuses (leur nombre varie en fait de 2 à 25): les plus grands nombres ont été rencontrés chez des Spermacocées. Pollen en tétrades tétraédriques: Oxyanthus, Macrosphyra, Gardenia et divers genres appartenant tous à la tribu des Gardéniées. Pollen en polyades (ou massules): Massularia. Le diamètre équatorial des grains varie de (12)16 à 40 (100) µ. L'exine est ordinairement ornée de réticules, de granules ou de ponctuations. GYNECEE Disque annulaire charnu, petit ou± volumineux, rarement fendu en deux lobes (Virectaria mulliflora). Style allongé, unique, de longueur variable chez les espèces hétérostyles, généralement étroit, remarquablement épaissi à un certain niveau chez quelques Cuviera, glabre ou pubescent. Le stigmate est ± massif chez les Gardéniées, calyptréiforme chez les Vanguériées et chez Mitragyna, souvent ± lobé; les lobes peuvent être claviformes, spatulés ou effilés. Chaque lobe stigmatique correspond au sommet d'une feuille carpellaire; il y a donc en pratique autant de loges d'ovaire que de lobes, sauf dans le cas de certaines Gardéniées à ovaire non cloisonné. Les papilles stigmatiques sont ± localisées sur le stigmate, disposées en taches (Uncaria, Nauclea) ou surfaces ± nettement délimitées. La surface papillifère des lobes peut être limitée à la face interne (Bertiera) ou s'étaler ± largement sur les côtés de chaque lobe. Ovaire fondamentalement infère, très exceptionnellement supère (Gaertnera et, en Amérique, Pagamea) et jamais alors très distinctement avant la nouaison. L'ovaire est sphérique, conique ou oblong, parfois orné de côtes méridiennes. Les placentas, masses charnues porteuses d'ovules et généralement assez distinctes des cloisons ou des parois de l'ovaire, sont issus des marges des feuilles carpellaires. Ces dernières,pièces élémentaires de l'ovaire, peuvent être largement déployées et former un ensemble uniloculaire à placentation pariétale (Gardenia, Calochone, Polycoryne), ou ± enroulées et refermées sur elles-mêmes d'où une placentation axile qui est réalisée chez la majorité des genres. La masse placentaire s'individualise parfois du fait du rétrécissement de son attache; le placenta est alors pelté: le pied est souvent une mince lame verticale, parfois un stipe grêle (diverses Hédyotidées); il peut être ascendant (Oldenlandia Pl. 11 fig. 3-5 ) ou descendant (Pseudosabicea Mildbraedii Pl. 24 fig. 14 ). Dans la plupart des genres l'ovaire se compose de deux feuilles carpellaires, il est donc biloculaire. On trouve 3, 4 ou 5 loges et plus rarement jusqu'à 12 loges (Lasianthus). Il y a parfois des cloisons supplémentaires incomplètes entre les sommets de placentas bilobés ou fendus en V (Pauridiantha, Stelecantha). Les ovules sont en nombre variable dans chaque loge; ils sont le plus souvent soit solitaires soit en grand nombre. Quelques genres seulement, principalement chez des Gardéniées, ont, par loge un nombre réduit d'ovules. Un seul ovule peut se développer d'où certains fruits monospermes (certains Canthium, Crateris-permum, Rutidea). Les ovules sont anatropes et orientés de façon variable, dressés, horizontaux ou pendants; ils sont ténuinucellés, à un seul tégument, non vascularisés et à funicule très court ou nul, rarement long (Nauclea). BIOLOGIE FLORALE Le rythme de la floraison est variable; il est synchrone dans le cas où toutes le fleurs d'une même inflorescence s'épanouissent en même temps (Nauclea, Pavetta, Coffea). Le rythme est asynchrone lorsqu l'épanouissement des fleurs est échelonné dans l'inflorescence (Psychotria, Sabicea, Bertiera, Otomeria). L'allogamie est favorisée par divers mécanismes floraux. La protandrie est sans doute le plus primitif de ces mécanismes; elle favorise la dispersion du pollen avant que les parties fertiles du stigmate soient découvertes (Bertiera). Le mécanisme ixoroïde qui intéresse plusieurs tribus en particulier les Ixorées, est une forme améliorée de la protandrie qui peut être comparée au « mécanisme de piston » des Composées. L'hétérostylie est peut-être plus évoluée; c'est une structure qui favorise dans certaines fleurs l'exposition des papilles stigmatiques, et dans d'autres fleurs la dispersion du pollen. L'autostérilité a été reconnue chez certaines espèces hétérostyles (Mussaenda erythrophylla, M. elegans). La dioécie est rare, au moins en Afrique, elle se présente comme un cas extrême d'hétérostylie (Mussaenda tristigmatica, M. isertiana). La monoécie également rare existe chez Atractogyne. Les fleurs sont le plus souvent pollinisées par les insectes ailés. Certaines grosses fleurs à anthèse nocturne sont très probablement adaptées à la pollinisation par les chauves-souris (Gardé-niées). En Amérique de nombreuses corolles sont adaptées (forme, port, couleur) à la pollinisation par les colibris; des cas similaires seraient à rechercher chez les Rubiaceae gabonaises. L'attractivité des fleurs est réalisée ordinairement par la couleur de la corolle (blanc, jaune, jaune-orangé, rouge, violet, brun, vert vif, bleu) et par la dimension du limbe corollin dans sa partie exposée. Cette fonction est parfois assurée par le calice ou l''involucre. Certaines fleurs sont très odorantes {Coffea, Psilanthus, nombreuses Gardéniées). Le moment de l'anthèse varie suivant l'espèce au cours des 24 H; il est parfois du soir, parfois au contraire très matinal. INFRUTESCENCE ET FRUIT Deux tendances biologiques se distinguent parmi les infrutescences de certains genres suivant que le taux de reproduction (nombre de fruits comparé au nombre de fleurs) est bas ou élevé. Le premier cas se rapporte souvent à des plantes reconnues comme plus primitives (nombreuses Gardéniées); les taux élevés se rencontrent dans des groupes que l'on s'accorde généralement à considérer comme plus évolués. Les fruits sont simples, plus rarement composés-syncarpiques (Nauclea, Morinda). Ils peuvent être ± charnus (syncarpes, baies, cabosses, drupes mono, oligo ou polyspermes). Beaucoup de genres ont des fruits charnus, colorés, globuleux et d'environ 1 cm de diamètre (Mussaendées, Ixorées, Psychotriées, Bertiera). L'attractivité des fruits charnus est réalisée par la couleur souvent vive de l'épiderme (blanc, jaune, orangé, rouge, grenat, violet, bleu, noir); certains fruits de teinte foncée sont rehaussés à la vue par les axes d'infrutescence colorés et parfois même accrescents-succulents (quelques Psychotriées). Les plus gros fruits sont du type cabosse, ils atteignent jusqu'à 15-20 cm de diamètre chez Rothmannia. La maturation des fruits charnus est parfois lente et très progressive (cabosses, baies ± sèches); parfois au contraire elle est marquée par un accroissement remarquable des tissus charnus qui se gonflent d'eau au stade ultime (Sabicea, Bertiera, Psychotria). Les fruits secs sont le plus souvent capsulaires, à déhiscence loculicide ou septicide, parfois à bec apical s'ouvrant en clapet. Les plus petits fruits sont des capsules d'env. 2 mm (espèces herbacées). Les fruits secs sont articulés caducs ou au contraire parfois persistants après la dispersion des graines. La famille est surtout très abondamment représentée dans les zones de forêts denses bien qu'en fait peu de genres soient typiquement des plantes d'ombre. Certains genres sont essentiellement représentés dans des régions à saison sèche très marquée et prolongée (Feretia, Gardenia, Borreria, Fadogia, Macrosphyra, Crossopteryx), donc peu ou pas représentés au Gabon. On y trouve toutefois des Rubiaceae de savanes, herbes annuelles ou même pyrophytes. A l'inverse, beaucoup de Rubiaceae sont liées à des formations marécageuses douces ou salées, mais seul le genre américain Limnosipanea est vraiment aquatique. Parmi les herbacées, un certain nombre d'espèces sont des rudérales. ENTRENOEUDS, EPINES ET CROCHETS Les entrenoeuds cylindriques ou quadrangulaires sont parfois modifiés par des myrmécodomaties ou cavités médullaires habitées par des fourmis (Rothmannia, Cuviera, Canthium, Vangueriopsis, Nauclea, Heinsia). Les noeuds ou même les entrenoeuds peuvent émettre des racines adventives, soit au niveau du sol (lianes rampantes), soit dans un terreau epiphyte souvent retenu par les stipules. Il n'y a jamais de vrilles, mais parfois des épines (Xeromphis, Gardenia, Didymosalpynx, Cuviera, Canthium, Vangueria, Plec-troniella, Rutidea) ou des crochets (Uncaria). FEUILLES, STIPULES ET GLANDES SOUS-STIPULAIRES Les feuilles sont simples et entières (le remarquable et très archaïque genre Pentagonia d'Amérique fait exception), opposées décussées, jamais subopposées, parfois verticillées (Fadogia, Temnocalyx, Adina, Pausinystalia, Schumanniophyton). Les feuilles sont parfois inégales dans une même paire (anisophyllie): des réductions unilatérales très fortes ou même totales s'observent dans le genre Pseudosabicea. Le limbe n'est jamais denté mais la marge est finement denticulée chez certains Lasianthus. La nervation du limbe est de type penné. Des domaties foliaires sont fréquentes aux aisselles de certaines nervures dans de nombreux genres; elles ne sont pas absolument constantes chez toutes les espèces d'un même genre ni dans toutes le populations d'une même espèce. Des galles d'origine bactérienne se rencontrent dans certains genres (Pavetta, Tricalysia, Psychotria). Les bactéries qu'elles contiennent sont totalement intégrées à la plante; elle sont présentes dans la graine et se perpétuent d'une génération à l'autre à travers la reproduction sexuée. Ces galles présentent des formes spécifiques et sont d'un grand intérêt pour la systématique. Le pétiole est rarement nul et présente le plus souvent un canal adaxial; les bords du canal qui sont en continuité avec les marges du limbe, sont en outre parfois connées aux stipules (Hédyotidées). Les stipules interpétiolaires sont toujours présentes, réduites ou développées, parfois caduques, uni, bi ou multidentées, parfois soudées en ochréa à l'intérieur des pétioles (Gardenia, Gaertnera, Bertiera). Les stipules, de même que les lobes calycinaux, présentent toujours vers leur base, en position interne ou latérale, des organes glandulaires qui secrètent des cérides; ces cérocystes sont généralement accompagnés de poils épidermiques. Devenus inutiles après le développement des organes qu'ils accompagnent, les cérocystes subsistent sous forme de petits denticules aigus noirs ou brunâtres. II n'existe pas de latex chez les Rubiaceae, mais les plaies peuvent exsuder certaines gommes. OXALATE DE CALCIUM L'oxalate de calcium est extrêmement fréquent, sinon même constant chez les Rubiaceae. Il se présente sous des formes cristallisées variables telles que macles, oursins ou raphides. Les raphides semblent prédominer chez les Rubiaceae herbacées (Hédyotidées, Spermacocées, Rubiées), mais des arbustes et des arbrisseaux en sont aussi pourvus (Psychotriées, Morindées, Urophyllées, Cratérispermées). La constance des raphides au niveau des tribus citées et de quelques autres a été retenue par certains auteurs pour distinguer une sous-famille des Rubioïdées, pourvue de raphides, d'une sous-famille des Cinchonoïdées dans laquelle l'oxalate n'est connu que sous forme de macles ou d'orsins (tribus des Naucléées, Cinchonées, Mussaendées, Gardéniées; Ixorées, Vanguériées etc.) Malgré l'opinion de Verdcourt ( Bull. J. R. Brux. 28 1958 ), cette division de base n'a pas été suivie, dans la présente flore. INFLORESCENCES Les inflorescences sont de types variés, terminales, subterminales ou axillaires; elles peuvent être uni, pauci ou multiflores et se présenter en cymes, panicules, grappes (généralement composées de cymes contractées, très rarement simples par appauvrissement des cymes latérales comme chez Bertiera Chevalieri), glo-mérules ou capitules; ces derniers sphériques ou non, syncarpiques ou non, avec ou sans involucre. La cauliflorie est assez rare (Slelecantha cauliflora, Ecpoma geanthum). Les bractées florales sont recaulescentes ou non, vestigielles ou protectrices (Mitragyna rubrostipulâta, Cuviera Letestui), attractives ou non. Les bractées sont parfois absentes à certaines ramifications inflorescentielles (quelques Sabicea) ou entre les fleurs de certains capitules (Burtt-davya, Breonia). L'involucre de certaines espèces est formé de pièces libres ou soudées entre elles; il se développe habituellement à partir des préfeuilles portées par le pédoncule de l'inflorescence (Sabicea, Stipularia, Cephaelis). FLEURS, PERIANTHE ET ANDROCEE Les fleurs sont hermaphrodites, très rarement unisexuées ou polygames. Elles peuvent être toutes semblables (isostylie) ou de deux types différents (hétérostylie): les fleurs à filets staminaux longs et à style court sont dites brévistyles; les fleurs à filets staminaux courts et à style long sont dites longistyles. Ces deux types floraux se présentent toujours sur des pieds différents, et la fécondation ne peut s'effectuer que par pollinisation croisée entre ces deux types de pieds. Le réceptacle est enveloppant et soudé à l'ovaire, d'où la position infère de ce dernier par rapport au périanthe. Calice gamosépale à (3)4-5(8) lobes d'aspect variable, égaux ou non, parfois très réduits à nuls, ou au contraire plus ou moins foliacés, imbriqués, contortés ou espacés. Un ou plusieurs sépales foliacés peuvent avoir un développement important et jouer un rôle attractif par leur couleur voyante (Mussaendées, plusieurs genres). Corolle gamopétale actinomorphe, très rarement ± zygo-morphe (Posoqueria en Amérique), parfois à tube i coudé (Chas-salia) ou courbé. Nombre de lobes de 3 à 10, ordinairement 4-5; préfloraison souvent contortée ou valvaire, parfois valvaire indupliquée, plus rarement quinconciale. Les lobes ou pétales sont ± réfléchis ou courbés extérieurement à l'anthèse, étalés ou parfois érigés. Le tube peut être long (jusqu'à 20 cm chez certaines Gardéniées)ou ± court, charnu ou non. Pilosité interne variable, parfois discontinue en zones annulaires ou en bandes verticales; poils ± abondants, ± fins, dressés ou rabattus, parfois fournis et saillants au dessus de la gorge. Les étamines sont en même nombre que les pétales; les filets sont soudés entre ces derniers. Les anthères sont situées à une hauteur variable, soit incluses, à un niveau ± bas dans le tube, soit exsertes, avec des filets de longueur très variable. L'anthère est introrse, basi ou dorsifixe, ± oblongue, parfois sagittée, à 2 loges bilocellées longitudinalement, rarement multilocellées tranversalement (Dictyandra et, en Amérique, Isertia). Sous l'insertion des filets et dans la partie étroite du tube, on rencontre dans certains genres, des fentes en boutonnières interpétalaires accompagnées, sur une petite longueur, d'un décollement des filets eux-mêmes. POLLEN Dans le cas général, le pollen se présente en grains simples isopolaires à 3 apertures de type colporus (sillons longitudinaux n'atteignant pas les pôles, avec un pore médian). Diverses exceptions sont à signaler: Sillons sans pores apparents: Rubia, Borreria. Pores sans sillons: Vanguériées, Psychotriées, Craterispermum, Mussaenda, Stipularia. Apertures nombreuses (leur nombre varie en fait de 2 à 25): les plus grands nombres ont été rencontrés chez des Spermacocées. Pollen en tétrades tétraédriques: Oxyanthus, Macrosphyra, Gardenia et divers genres appartenant tous à la tribu des Gardéniées. Pollen en polyades (ou massules): Massularia. Le diamètre équatorial des grains varie de (12)16 à 40 (100) µ. L'exine est ordinairement ornée de réticules, de granules ou de ponctuations. GYNECEE Disque annulaire charnu, petit ou± volumineux, rarement fendu en deux lobes (Virectaria mulliflora). Style allongé, unique, de longueur variable chez les espèces hétérostyles, généralement étroit, remarquablement épaissi à un certain niveau chez quelques Cuviera, glabre ou pubescent. Le stigmate est ± massif chez les Gardéniées, calyptréiforme chez les Vanguériées et chez Mitragyna, souvent ± lobé; les lobes peuvent être claviformes, spatulés ou effilés. Chaque lobe stigmatique correspond au sommet d'une feuille carpellaire; il y a donc en pratique autant de loges d'ovaire que de lobes, sauf dans le cas de certaines Gardéniées à ovaire non cloisonné. Les papilles stigmatiques sont ± localisées sur le stigmate, disposées en taches (Uncaria, Nauclea) ou surfaces ± nettement délimitées. La surface papillifère des lobes peut être limitée à la face interne (Bertiera) ou s'étaler ± largement sur les côtés de chaque lobe. Ovaire fondamentalement infère, très exceptionnellement supère (Gaertnera et, en Amérique, Pagamea) et jamais alors très distinctement avant la nouaison. L'ovaire est sphérique, conique ou oblong, parfois orné de côtes méridiennes. Les placentas, masses charnues porteuses d'ovules et généralement assez distinctes des cloisons ou des parois de l'ovaire, sont issus des marges des feuilles carpellaires. Ces dernières,pièces élémentaires de l'ovaire, peuvent être largement déployées et former un ensemble uniloculaire à placentation pariétale (Gardenia, Calochone, Polycoryne), ou ± enroulées et refermées sur elles-mêmes d'où une placentation axile qui est réalisée chez la majorité des genres. La masse placentaire s'individualise parfois du fait du rétrécissement de son attache; le placenta est alors pelté: le pied est souvent une mince lame verticale, parfois un stipe grêle (diverses Hédyotidées); il peut être ascendant (Oldenlandia Pl. 11 fig. 3-5 ) ou descendant (Pseudosabicea Mildbraedii Pl. 24 fig. 14 ). Dans la plupart des genres l'ovaire se compose de deux feuilles carpellaires, il est donc biloculaire. On trouve 3, 4 ou 5 loges et plus rarement jusqu'à 12 loges (Lasianthus). Il y a parfois des cloisons supplémentaires incomplètes entre les sommets de placentas bilobés ou fendus en V (Pauridiantha, Stelecantha). Les ovules sont en nombre variable dans chaque loge; ils sont le plus souvent soit solitaires soit en grand nombre. Quelques genres seulement, principalement chez des Gardéniées, ont, par loge un nombre réduit d'ovules. Un seul ovule peut se développer d'où certains fruits monospermes (certains Canthium, Crateris-permum, Rutidea). Les ovules sont anatropes et orientés de façon variable, dressés, horizontaux ou pendants; ils sont ténuinucellés, à un seul tégument, non vascularisés et à funicule très court ou nul, rarement long (Nauclea). BIOLOGIE FLORALE Le rythme de la floraison est variable; il est synchrone dans le cas où toutes le fleurs d'une même inflorescence s'épanouissent en même temps (Nauclea, Pavetta, Coffea). Le rythme est asynchrone lorsqu l'épanouissement des fleurs est échelonné dans l'inflorescence (Psychotria, Sabicea, Bertiera, Otomeria). L'allogamie est favorisée par divers mécanismes floraux. La protandrie est sans doute le plus primitif de ces mécanismes; elle favorise la dispersion du pollen avant que les parties fertiles du stigmate soient découvertes (Bertiera). Le mécanisme ixoroïde qui intéresse plusieurs tribus en particulier les Ixorées, est une forme améliorée de la protandrie qui peut être comparée au « mécanisme de piston » des Composées. L'hétérostylie est peut-être plus évoluée; c'est une structure qui favorise dans certaines fleurs l'exposition des papilles stigmatiques, et dans d'autres fleurs la dispersion du pollen. L'autostérilité a été reconnue chez certaines espèces hétérostyles (Mussaenda erythrophylla, M. elegans). La dioécie est rare, au moins en Afrique, elle se présente comme un cas extrême d'hétérostylie (Mussaenda tristigmatica, M. isertiana). La monoécie également rare existe chez Atractogyne. Les fleurs sont le plus souvent pollinisées par les insectes ailés. Certaines grosses fleurs à anthèse nocturne sont très probablement adaptées à la pollinisation par les chauves-souris (Gardé-niées). En Amérique de nombreuses corolles sont adaptées (forme, port, couleur) à la pollinisation par les colibris; des cas similaires seraient à rechercher chez les Rubiaceae gabonaises. L'attractivité des fleurs est réalisée ordinairement par la couleur de la corolle (blanc, jaune, jaune-orangé, rouge, violet, brun, vert vif, bleu) et par la dimension du limbe corollin dans sa partie exposée. Cette fonction est parfois assurée par le calice ou l''involucre. Certaines fleurs sont très odorantes {Coffea, Psilanthus, nombreuses Gardéniées). Le moment de l'anthèse varie suivant l'espèce au cours des 24 H; il est parfois du soir, parfois au contraire très matinal. INFRUTESCENCE ET FRUIT Deux tendances biologiques se distinguent parmi les infrutescences de certains genres suivant que le taux de reproduction (nombre de fruits comparé au nombre de fleurs) est bas ou élevé. Le premier cas se rapporte souvent à des plantes reconnues comme plus primitives (nombreuses Gardéniées); les taux élevés se rencontrent dans des groupes que l'on s'accorde généralement à considérer comme plus évolués. Les fruits sont simples, plus rarement composés-syncarpiques (Nauclea, Morinda). Ils peuvent être ± charnus (syncarpes, baies, cabosses, drupes mono, oligo ou polyspermes). Beaucoup de genres ont des fruits charnus, colorés, globuleux et d'environ 1 cm de diamètre (Mussaendées, Ixorées, Psychotriées, Bertiera). L'attractivité des fruits charnus est réalisée par la couleur souvent vive de l'épiderme (blanc, jaune, orangé, rouge, grenat, violet, bleu, noir); certains fruits de teinte foncée sont rehaussés à la vue par les axes d'infrutescence colorés et parfois même accrescents-succulents (quelques Psychotriées). Les plus gros fruits sont du type cabosse, ils atteignent jusqu'à 15-20 cm de diamètre chez Rothmannia. La maturation des fruits charnus est parfois lente et très progressive (cabosses, baies ± sèches); parfois au contraire elle est marquée par un accroissement remarquable des tissus charnus qui se gonflent d'eau au stade ultime (Sabicea, Bertiera, Psychotria). Les fruits secs sont le plus souvent capsulaires, à déhiscence loculicide ou septicide, parfois à bec apical s'ouvrant en clapet. Les plus petits fruits sont des capsules d'env. 2 mm (espèces herbacées). Les fruits secs sont articulés caducs ou au contraire parfois persistants après la dispersion des graines. La famille est surtout très abondamment représentée dans les zones de forêts denses bien qu'en fait peu de genres soient typiquement des plantes d'ombre. Certains genres sont essentiellement représentés dans des régions à saison sèche très marquée et prolongée (Feretia, Gardenia, Borreria, Fadogia, Macrosphyra, Crossopteryx), donc peu ou pas représentés au Gabon. On y trouve toutefois des Rubiaceae de savanes, herbes annuelles ou même pyrophytes. A l'inverse, beaucoup de Rubiaceae sont liées à des formations marécageuses douces ou salées, mais seul le genre américain Limnosipanea est vraiment aquatique. Parmi les herbacées, un certain nombre d'espèces sont des rudérales. Trees, shrubs or rarely herbs Leaves opposite or rarely verticillate, entire; stipules inter- or intra-petiolar, often connate, rarely leafy and not distinguishable from the leaves Seeds rarely winged, mostly with endosperm, the latter rarely ruminate; embryo straight or curved Ovary inferior or rarely superior, 2- or more-celled, with axile, apical or basal placentas, or rarely 1-celled with parietal placentas; style often slender; ovules 1 to many Fruit a capsule, berry or drupe Corolla epigynous, more or less tubular, rarely campanulate; lobes 4-12, contorted, imbricate or valvate Stamens epipetalous, as many as and alternate with the corolla-lobes; anthers mostly separate, 2-celled, opening lengthwise or rarely by terminal pores, rarely transversely septate Flowers usually hermaphrodite, actinomorphic or very rarely slightly zygomorphic, solitary to capitate Calyx adnate to the ovary Leaves opposite or rarely verticillate, entire; stipules inter- or intra-petiolar, often connate, rarely leafy and not distinguishable from the leaves Seeds rarely winged, mostly with endosperm, the latter rarely ruminate; embryo straight or curved Ovary inferior or rarely superior, 2- or more-celled, with axile, apical or basal placentas, or rarely 1-celled with parietal placentas; style often slender; ovules 1 to many Fruit a capsule, berry or drupe Corolla epigynous, more or less tubular, rarely campanulate; lobes 4-12, contorted, imbricate or valvate Stamens epipetalous, as many as and alternate with the corolla-lobes; anthers mostly separate, 2-celled, opening lengthwise or rarely by terminal pores, rarely transversely septate Flowers usually hermaphrodite, actinomorphic or very rarely slightly zygomorphic, solitary to capitate Calyx adnate to the ovary Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; endosperm present (save in Guettardeae), entire or ruminate; embryo straight or rarely curved; radicle erect or horizontal, mostly longer than the cotyledons, orientation pendulous Fruit small to very large, 2–many-seeded, dehiscent (capsules either loculicidal, septicidal, opening by a beak or infrequently circumscissile, or splitting into mericarps), or indehiscent (berries, including forms with woody walls, or drupes), occasionally (eg in Nauclea and Morinda) united to form syncarps; if drupes containing one-seeded pyrenes thin- or thick-walled, opening by pre-formed germination slits or not, or less often a multi-seeded stone Ovary inferior, rarely half-inferior or superior (in Gaertnera), syncarpous of 2–10(12 or more) carpels, but predominantly of 2, and therefore predominantly 2-locular, but 3–10(12) (in Urophylleae can appear higher than actual carpel number due to supplementary incomplete partitions), or infrequently uni-locular (or partly so); ovules l–numerous per locule; placentation axile (attached to septum at apex, middle or base, usually on a placenta, often embedded in fleshy placentas) or infrequently (in some Gardenieae) parietal; ovules anatropous; style simple, usually long (but very short in Rubieae) and narrow, at the top either cylindrical, clavate, or otherwise modified to form a pollen presenter (the actual stigmatic surface sometimes confined to specific areas, eg the inner faces of the lobes**), or divided into 2–many (according to number of carpels) linear, spathulate or clavate stigmatic lobes Disk usually functioning as a nectary, positioned above the ovary inside the base of the calyx limb, annular to cushion-shaped or tubular, sometimes 2-lobed, occasionally fused to base of calyx limb-tube (Naucleeae) or absent (in wind-pollinated flowers) Pollen various, mostly simple, isopolar and 3- colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely in polyads Stamens usually as many as the corolla lobes and alternate with them, epipetalous or not (some New World tribes only); anthers basi- or more often dorsifixed, introrse rarely porate (not in the Flora Zambesiaca area), the thecae rarely transversely multilocellate Corolla predominantly white but sometimes coloured, small to large and showy, gamopetalous, mostly salver- shaped to funnel-shaped or less often campanulate, occasionally tube very short, the tube rarely curved, (3)4–5(11)-lobed, the lobes contorted (mostly to the left, infrequently to the right) or valvate (sometimes induplicate or reduplicate), with or without a contact zone (i.e. thickened margin), less often imbricate (tab. 73/B–D) Calyx gamosepalous, the tube (i.e. calyx tube**) mostly adnate to the ovary, the limb with tubular part (i.e. limb-tube) present or absent, truncate or bearing minute teeth to well developed lobes (tab. 73/A1–A4), valvate (often separated by sinuses), or less often imbricate or contorted in aestivation, in a few genera 1–several lobes sometimes slightly to considerably enlarged to form a leaf-like often coloured blade (calycophyll) (tab. 73/A5) Stipules interpetiolar or occasionally intrapetiolar (mostly New World taxa); lobes shortly fused above the petioles and sometimes forming a sheath, or lobes free, entire, bifid or rarely laciniate, or particularly in herbaceous genera, fimbriate, often tipped with or separated by colleters (mucilaginous glands) (tab. 74), often with colleters inside the limb, especially towards the base Inflorescences terminal or axillary, basically thyrsoid, variously aggregated into panicles etc., occasionally in globose heads sometimes to an extent that the ovaries are adnate, or sometimes flowers solitary; bracts vestigial to well developed, even conspicuous Flowers regular or slightly to distinctly (not in Africa) zygomorphic, hermaphrodite or less often unisexual, homostylous, in which case very often protandrous, with or without pollen presentation (tab. 73/F,G), or rarely protogynous (not in Africa), or heterostylous with 2 or less often 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous) (tab. 73/E) Small to large trees, shrubs (including suffrutices from woody rootstocks) or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; raphides (tab. 1/7) present or absent; crystal sand absent or present (these two mutually exclusive) Leaves opposite or occasionally verticillate, decussate, almost always entire, very rarely sparsely toothed or lobed (not in the Flora Zambesiaca area), always obviously stipulate (save in some Rubieae, where the stipules may be considered leaf-like or almost absent according to interpretation); domatia (mite associated pits or tufts of hairs) very often present axils of lateral nerves on the leaf lower surface; bacterial nodules present in a few genera Flowers regular or slightly to distinctly (not in Africa) zygomorphic, hermaphrodite or less often unisexual, homostylous, in which case very often protandrous, with or without pollen presentation (tab. 73/F,G), or rarely protogynous (not in Africa), or heterostylous with 2 or less often 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous) (tab. 73/E) Corolla predominantly white but sometimes coloured, small to large and showy, gamopetalous, mostly salver- shaped to funnel-shaped or less often campanulate, occasionally tube very short, the tube rarely curved, (3)4–5(11)-lobed, the lobes contorted (mostly to the left, infrequently to the right) or valvate (sometimes induplicate or reduplicate), with or without a contact zone (i.e. thickened margin), less often imbricate (tab. 73/B–D) Calyx gamosepalous, the tube (i.e. calyx tube**) mostly adnate to the ovary, the limb with tubular part (i.e. limb-tube) present or absent, truncate or bearing minute teeth to well developed lobes (tab. 73/A1–A4), valvate (often separated by sinuses), or less often imbricate or contorted in aestivation, in a few genera 1–several lobes sometimes slightly to considerably enlarged to form a leaf-like often coloured blade (calycophyll) (tab. 73/A5) Pollen various, mostly simple, isopolar and 3- colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely in polyads Stamens usually as many as the corolla lobes and alternate with them, epipetalous or not (some New World tribes only); anthers basi- or more often dorsifixed, introrse rarely porate (not in the Flora Zambesiaca area), the thecae rarely transversely multilocellate Ovary inferior, rarely half-inferior or superior (in Gaertnera), syncarpous of 2–10(12 or more) carpels, but predominantly of 2, and therefore predominantly 2-locular, but 3–10(12) (in Urophylleae can appear higher than actual carpel number due to supplementary incomplete partitions), or infrequently uni-locular (or partly so); ovules l–numerous per locule; placentation axile (attached to septum at apex, middle or base, usually on a placenta, often embedded in fleshy placentas) or infrequently (in some Gardenieae) parietal; ovules anatropous; style simple, usually long (but very short in Rubieae) and narrow, at the top either cylindrical, clavate, or otherwise modified to form a pollen presenter (the actual stigmatic surface sometimes confined to specific areas, eg the inner faces of the lobes**), or divided into 2–many (according to number of carpels) linear, spathulate or clavate stigmatic lobes Disk usually functioning as a nectary, positioned above the ovary inside the base of the calyx limb, annular to cushion-shaped or tubular, sometimes 2-lobed, occasionally fused to base of calyx limb-tube (Naucleeae) or absent (in wind-pollinated flowers) Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; endosperm present (save in Guettardeae), entire or ruminate; embryo straight or rarely curved; radicle erect or horizontal, mostly longer than the cotyledons, orientation pendulous Fruit small to very large, 2–many-seeded, dehiscent (capsules either loculicidal, septicidal, opening by a beak or infrequently circumscissile, or splitting into mericarps), or indehiscent (berries, including forms with woody walls, or drupes), occasionally (eg in Nauclea and Morinda) united to form syncarps; if drupes containing one-seeded pyrenes thin- or thick-walled, opening by pre-formed germination slits or not, or less often a multi-seeded stone Stipules interpetiolar or occasionally intrapetiolar (mostly New World taxa); lobes shortly fused above the petioles and sometimes forming a sheath, or lobes free, entire, bifid or rarely laciniate, or particularly in herbaceous genera, fimbriate, often tipped with or separated by colleters (mucilaginous glands) (tab. 74), often with colleters inside the limb, especially towards the base Inflorescences terminal or axillary, basically thyrsoid, variously aggregated into panicles etc., occasionally in globose heads sometimes to an extent that the ovaries are adnate, or sometimes flowers solitary; bracts vestigial to well developed, even conspicuous Small to large trees, shrubs or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; tissues in many tribes containing abundant rhaphides Leaves opposite or verticillate, decussate, almost always entire, very rarely (not in Africa) palmatifid, toothed or finely denticulate, always obviously stipulate (save in some Rubieae, where the stipules may be considered foliar or almost absent according to interpretation), the stipules interpetiolar or intrapetiolar, entire or, particularly in herbaceous genera, variously divided into lobes or fimbriae, often tipped or separated by mucilaginous hairs known as colleters and often with colleters inside the base; the leaves in certain tribes sometimes contain small bacterial nodules Corolla small to large and showy, gamopetalous, rotate to salver-shaped or funnel-shaped, the tube often very long, (3)4–5(11)-lobed, the lobes mostly contorted or valvate, sometimes valvate-induplicate, rarely imbricate or quincuncial Calyx gamosepalous, the tube mostly adnate to the ovary, (3)4–5(8)-toothed or lobed, sometimes only minutely so, with open, valvate, imbricate or contorted aestivation, 1 or several lobes sometimes slightly to very considerably enlarged to form a leafy often coloured lamina Flowers rarely solitary, mostly in various terminal or axillary inflorescences, all basically cymose but variously aggregated into panicles, etc., occasionally in globose heads to an extent that the ovaries are adnate; bracts vestigial to well developed, even conspicuous; flowers usually hermaphrodite, rarely unisexual, regular or nearly so (except in Posoqueria (America)) or corolla tube rarely curved, homostylous or quite often heterostylous with 2 or rarely 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous)) Ovary inferior, rarely half-inferior or (in Gaertnera) superior, syncarpous of 2–5 or more carpels, but predominantly of 2 and therefore predominantly 2-locular, but 3–5 or even 12 or more (eg in Urophylleae due to supplementary incomplete partitions); placentation axile or (in some Gardenieae) parietal; ovules 1-many per locule, often embedded in fleshy placentas, erect, basal or horizontal, anatropous; style simple, usually long and narrow, the “stigma” either cylindrical, clavate, or otherwise modified to form a “receptaculum pollinis” or divided into 2-many linear, spathulate or clavate lobes, the actual stigmatic surface sometimes confined to certain areas, eg the inner faces of the lobes Disc often present, 2-lobed or tubular Pollen various, mostly simple, isopolar and 3-colporate, but sometimes porate, the number of colpi or pores varying from 2–25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely polyads Stamens usually as many as the corolla-lobes and alternate with them, epipetalous; anthers basi-or dorsifixed, introrse, the thecae rarely multilocellate transversely Leaves opposite or occasionally verticillate, decussate, almost always entire, very rarely sparsely toothed or lobed (not in the Flora Zambesiaca area), always obviously stipulate (save in some Rubieae, where the stipules may be considered leaf-like or almost absent according to interpretation); domatia (mite associated pits or tufts of hairs) very often present axils of lateral nerves on the leaf lower surface; bacterial nodules present in a few genera Small to large trees, shrubs (including suffrutices from woody rootstocks) or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; raphides (tab. 1/7) present or absent; crystal sand absent or present (these two mutually exclusive) Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; albumen present (save in Guettardeae); embryo straight or rarely curved, the radicle mostly longer than the cotyledons Fruit small to quite large (0|2–20 cm.), a capsule, berry or drupe or indehiscent or woody, occasionally (eg in Naulea and Morinda) united to form syncarps, (1)2-many-seeded, if capsules then loculicidal or septicidal or opening by a beak Fruit small to very large, 2–many-seeded, dehiscent (capsules either loculicidal, septicidal, opening by a beak or infrequently circumscissile, or splitting into mericarps), or indehiscent (berries, including forms with woody walls, or drupes), occasionally (eg in Nauclea and Morinda) united to form syncarps; if drupes containing one-seeded pyrenes thin- or thick-walled, opening by pre-formed germination slits or not, or less often a multi-seeded stone Ovary inferior, rarely half-inferior or superior (in Gaertnera), syncarpous of 2–10(12 or more) carpels, but predominantly of 2, and therefore predominantly 2-locular, but 3–10(12) (in Urophylleae can appear higher than actual carpel number due to supplementary incomplete partitions), or infrequently uni-locular (or partly so); ovules l–numerous per locule; placentation axile (attached to septum at apex, middle or base, usually on a placenta, often embedded in fleshy placentas) or infrequently (in some Gardenieae) parietal; ovules anatropous; style simple, usually long (but very short in Rubieae) and narrow, at the top either cylindrical, clavate, or otherwise modified to form a pollen presenter (the actual stigmatic surface sometimes confined to specific areas, eg the inner faces of the lobes**), or divided into 2–many (according to number of carpels) linear, spathulate or clavate stigmatic lobes Disk usually functioning as a nectary, positioned above the ovary inside the base of the calyx limb, annular to cushion-shaped or tubular, sometimes 2-lobed, occasionally fused to base of calyx limb-tube (Naucleeae) or absent (in wind-pollinated flowers) Pollen various, mostly simple, isopolar and 3- colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely in polyads Stamens usually as many as the corolla lobes and alternate with them, epipetalous or not (some New World tribes only); anthers basi- or more often dorsifixed, introrse rarely porate (not in the Flora Zambesiaca area), the thecae rarely transversely multilocellate Corolla predominantly white but sometimes coloured, small to large and showy, gamopetalous, mostly salver- shaped to funnel-shaped or less often campanulate, occasionally tube very short, the tube rarely curved, (3)4–5(11)-lobed, the lobes contorted (mostly to the left, infrequently to the right) or valvate (sometimes induplicate or reduplicate), with or without a contact zone (i.e. thickened margin), less often imbricate (tab. 73/B–D) Calyx gamosepalous, the tube (i.e. calyx tube**) mostly adnate to the ovary, the limb with tubular part (i.e. limb-tube) present or absent, truncate or bearing minute teeth to well developed lobes (tab. 73/A1–A4), valvate (often separated by sinuses), or less often imbricate or contorted in aestivation, in a few genera 1–several lobes sometimes slightly to considerably enlarged to form a leaf-like often coloured blade (calycophyll) (tab. 73/A5) Stipules interpetiolar or occasionally intrapetiolar (mostly New World taxa); lobes shortly fused above the petioles and sometimes forming a sheath, or lobes free, entire, bifid or rarely laciniate, or particularly in herbaceous genera, fimbriate, often tipped with or separated by colleters (mucilaginous glands) (tab. 74), often with colleters inside the limb, especially towards the base Inflorescences terminal or axillary, basically thyrsoid, variously aggregated into panicles etc., occasionally in globose heads sometimes to an extent that the ovaries are adnate, or sometimes flowers solitary; bracts vestigial to well developed, even conspicuous Flowers regular or slightly to distinctly (not in Africa) zygomorphic, hermaphrodite or less often unisexual, homostylous, in which case very often protandrous, with or without pollen presentation (tab. 73/F,G), or rarely protogynous (not in Africa), or heterostylous with 2 or less often 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous) (tab. 73/E) Small to large trees, shrubs (including suffrutices from woody rootstocks) or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; raphides (tab. 1/7) present or absent; crystal sand absent or present (these two mutually exclusive) Leaves opposite or occasionally verticillate, decussate, almost always entire, very rarely sparsely toothed or lobed (not in the Flora Zambesiaca area), always obviously stipulate (save in some Rubieae, where the stipules may be considered leaf-like or almost absent according to interpretation); domatia (mite associated pits or tufts of hairs) very often present axils of lateral nerves on the leaf lower surface; bacterial nodules present in a few genera Flowers regular or slightly to distinctly (not in Africa) zygomorphic, hermaphrodite or less often unisexual, homostylous, in which case very often protandrous, with or without pollen presentation (tab. 73/F,G), or rarely protogynous (not in Africa), or heterostylous with 2 or less often 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous) (tab. 73/E) Corolla predominantly white but sometimes coloured, small to large and showy, gamopetalous, mostly salver- shaped to funnel-shaped or less often campanulate, occasionally tube very short, the tube rarely curved, (3)4–5(11)-lobed, the lobes contorted (mostly to the left, infrequently to the right) or valvate (sometimes induplicate or reduplicate), with or without a contact zone (i.e. thickened margin), less often imbricate (tab. 73/B–D) Calyx gamosepalous, the tube (i.e. calyx tube**) mostly adnate to the ovary, the limb with tubular part (i.e. limb-tube) present or absent, truncate or bearing minute teeth to well developed lobes (tab. 73/A1–A4), valvate (often separated by sinuses), or less often imbricate or contorted in aestivation, in a few genera 1–several lobes sometimes slightly to considerably enlarged to form a leaf-like often coloured blade (calycophyll) (tab. 73/A5) Pollen various, mostly simple, isopolar and 3- colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely in polyads Stamens usually as many as the corolla lobes and alternate with them, epipetalous or not (some New World tribes only); anthers basi- or more often dorsifixed, introrse rarely porate (not in the Flora Zambesiaca area), the thecae rarely transversely multilocellate Ovary inferior, rarely half-inferior or superior (in Gaertnera), syncarpous of 2–10(12 or more) carpels, but predominantly of 2, and therefore predominantly 2-locular, but 3–10(12) (in Urophylleae can appear higher than actual carpel number due to supplementary incomplete partitions), or infrequently uni-locular (or partly so); ovules l–numerous per locule; placentation axile (attached to septum at apex, middle or base, usually on a placenta, often embedded in fleshy placentas) or infrequently (in some Gardenieae) parietal; ovules anatropous; style simple, usually long (but very short in Rubieae) and narrow, at the top either cylindrical, clavate, or otherwise modified to form a pollen presenter (the actual stigmatic surface sometimes confined to specific areas, eg the inner faces of the lobes**), or divided into 2–many (according to number of carpels) linear, spathulate or clavate stigmatic lobes Disk usually functioning as a nectary, positioned above the ovary inside the base of the calyx limb, annular to cushion-shaped or tubular, sometimes 2-lobed, occasionally fused to base of calyx limb-tube (Naucleeae) or absent (in wind-pollinated flowers) Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; endosperm present (save in Guettardeae), entire or ruminate; embryo straight or rarely curved; radicle erect or horizontal, mostly longer than the cotyledons, orientation pendulous Fruit small to very large, 2–many-seeded, dehiscent (capsules either loculicidal, septicidal, opening by a beak or infrequently circumscissile, or splitting into mericarps), or indehiscent (berries, including forms with woody walls, or drupes), occasionally (eg in Nauclea and Morinda) united to form syncarps; if drupes containing one-seeded pyrenes thin- or thick-walled, opening by pre-formed germination slits or not, or less often a multi-seeded stone Stipules interpetiolar or occasionally intrapetiolar (mostly New World taxa); lobes shortly fused above the petioles and sometimes forming a sheath, or lobes free, entire, bifid or rarely laciniate, or particularly in herbaceous genera, fimbriate, often tipped with or separated by colleters (mucilaginous glands) (tab. 74), often with colleters inside the limb, especially towards the base Inflorescences terminal or axillary, basically thyrsoid, variously aggregated into panicles etc., occasionally in globose heads sometimes to an extent that the ovaries are adnate, or sometimes flowers solitary; bracts vestigial to well developed, even conspicuous Small to large trees, shrubs or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; tissues in many tribes containing abundant rhaphides Leaves opposite or verticillate, decussate, almost always entire, very rarely (not in Africa) palmatifid, toothed or finely denticulate, always obviously stipulate (save in some Rubieae, where the stipules may be considered foliar or almost absent according to interpretation), the stipules interpetiolar or intrapetiolar, entire or, particularly in herbaceous genera, variously divided into lobes or fimbriae, often tipped or separated by mucilaginous hairs known as colleters and often with colleters inside the base; the leaves in certain tribes sometimes contain small bacterial nodules Corolla small to large and showy, gamopetalous, rotate to salver-shaped or funnel-shaped, the tube often very long, (3)4–5(11)-lobed, the lobes mostly contorted or valvate, sometimes valvate-induplicate, rarely imbricate or quincuncial Calyx gamosepalous, the tube mostly adnate to the ovary, (3)4–5(8)-toothed or lobed, sometimes only minutely so, with open, valvate, imbricate or contorted aestivation, 1 or several lobes sometimes slightly to very considerably enlarged to form a leafy often coloured lamina Flowers rarely solitary, mostly in various terminal or axillary inflorescences, all basically cymose but variously aggregated into panicles, etc., occasionally in globose heads to an extent that the ovaries are adnate; bracts vestigial to well developed, even conspicuous; flowers usually hermaphrodite, rarely unisexual, regular or nearly so (except in Posoqueria (America)) or corolla tube rarely curved, homostylous or quite often heterostylous with 2 or rarely 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous)) Ovary inferior, rarely half-inferior or (in Gaertnera) superior, syncarpous of 2–5 or more carpels, but predominantly of 2 and therefore predominantly 2-locular, but 3–5 or even 12 or more (eg in Urophylleae due to supplementary incomplete partitions); placentation axile or (in some Gardenieae) parietal; ovules 1-many per locule, often embedded in fleshy placentas, erect, basal or horizontal, anatropous; style simple, usually long and narrow, the “stigma” either cylindrical, clavate, or otherwise modified to form a “receptaculum pollinis” or divided into 2-many linear, spathulate or clavate lobes, the actual stigmatic surface sometimes confined to certain areas, eg the inner faces of the lobes Disc often present, 2-lobed or tubular Pollen various, mostly simple, isopolar and 3-colporate, but sometimes porate, the number of colpi or pores varying from 2–25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely polyads Stamens usually as many as the corolla-lobes and alternate with them, epipetalous; anthers basi-or dorsifixed, introrse, the thecae rarely multilocellate transversely Leaves opposite or occasionally verticillate, decussate, almost always entire, very rarely sparsely toothed or lobed (not in the Flora Zambesiaca area), always obviously stipulate (save in some Rubieae, where the stipules may be considered leaf-like or almost absent according to interpretation); domatia (mite associated pits or tufts of hairs) very often present axils of lateral nerves on the leaf lower surface; bacterial nodules present in a few genera Small to large trees, shrubs (including suffrutices from woody rootstocks) or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; raphides (tab. 1/7) present or absent; crystal sand absent or present (these two mutually exclusive) Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; albumen present (save in Guettardeae); embryo straight or rarely curved, the radicle mostly longer than the cotyledons Fruit small to quite large (0|2–20 cm.), a capsule, berry or drupe or indehiscent or woody, occasionally (eg in Naulea and Morinda) united to form syncarps, (1)2-many-seeded, if capsules then loculicidal or septicidal or opening by a beak Fls perfect, mostly 4(–8)-merous, epigynous, sympetalous, regular; cal mostly small, with open aestivation, or obsolete; stamens on the cor-tube, as many as and alternate with the lobes; ovary inferior, mostly 2(–5)-carpellate and plurilocular, with axile (or axile-basal or axile-apical) placentation; style slender, terminal, with lobed or capitate stigma, or (as in Galium) the styles distinct; ovules and seeds 1–many per locule; seeds with a dicotyledonous, usually straight embryo embedded in the oily endosperm; herbs or more often woody plants with simple, mostly entire, commonly decussately opposite lvs and interpetiolar (usually connate) stipules, or with whorled lvs and no stipules, the stipules typically bearing colleters within, or seldom the stipules reduced to mere interpetiolar lines; infls basically cymose. 450/6500, cosmop. but mostly trop. and subtrop. Flowers rarely solitary, mostly in various terminal or axillary inflorescences, all basically cymose but variously aggregated into panicles, etc., occasionally in globose heads to an extent that the ovaries are adnate; bracts vestigial to well developed, even conspicuous; flowers usually hermaphrodite, rarely unisexual, regular or nearly so (except in >i>Posoqueria (America)) or corolla-tube rarely curved, homostylous or quite often heterostylous with 2 or rarely 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous)) Calyx gamosepalous, the tube mostly adnate to the ovary, (3–)4–5(–8)-toothed or -lobed, sometimes only minutely so, with open, valvate, imbricate or contorted aestivation, 1 or several lobes sometimes slightly to very considerably enlarged to form a leafy often coloured lamina Small to large trees, shrubs or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; tissues in many tribes containing abundant rhaphides Leaves opposite or verticillate, decussate, almost always entire, very rarely (not in East Africa) palmatifid, toothed or finely denticulate, always obviously stipulate (save in some Rubieae, where the stipules may be considered foliar or almost absent according to interpretation), the stipules interpetiolar or intrapetiolar, entire or, particularly in herbaceous genera, variously divided into lobes or fimbrieae, often tipped or separated by mucilaginous hairs known as colleters and often with colleters inside the base; the leaves in certain tribes sometimes contain small bacterial nodules Corolla small to large and showy, gamopetalous, rotate to salver-shaped or funnel-shaped, the tube often very long, (3–)4–5(–11)-lobed, the lobes mostly contorted or valvate, sometimes valvate-induplicate, rarely imbricate or quincuncial Stamens usually as many as the corolla-lobes and alternate with them, epipetalous; anthers basi- or dorsifixed, introrse, the thecae rarely multilocellate transversely Pollen various, mostly simple, isopolar and 3-colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some >i>Gardenieae) in tetrads or rarely in polyads Disc often present, 2-lobed or tubular Ovary inferior, rarely half-inferior or (in >i>Gaertnera) superior, syncarpous of 2–5 or more carpels, but predominantly of 2 and therefore predominantly 2-locular, but 3–5 or even 12 or more (e.g. in >i>Urophylleae due to supplementary incomplete partitions); placentation axile or (in some >i>Gardenieae) parietal; ovules 1–many per locule, often embedded in fleshy placentas, erect, basal or horizontal, anatropous; style simple, usually long and narrow, the “stigma” either cylindrical, clavate, or otherwise modified to form a “receptaculum pollinis” or divided into 2–many linear, spathulate or clavate lobes, the actual stigmatic surface sometimes confined to certain areas, e.g. the inner faces of the lobes Fruit small to quite large (0.2–20 cm.), a capsule, berry or drupe or indehiscent or woody, occasionally (e.g. in >i>Nauclea and >i>Morinda) united to form syncarps, (1–)2–many-seeded, if capsules then loculicidal or septicidal or opening by a beak Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; albumen present (save in >i>Guettardeae); embryo straight or rarely curved, the radicle mostly longer than the cotyledons Calyx gamosepalous, the tube mostly adnate to the ovary, (3–)4–5(–8)-toothed or -lobed, sometimes only minutely so, with open, valvate, imbricate or contorted aestivation, 1 or several lobes sometimes slightly to very considerably enlarged to form a leafy often coloured lamina Small to large trees, shrubs or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; tissues in many tribes containing abundant rhaphides Leaves opposite or verticillate, decussate, almost always entire, very rarely (not in East Africa) palmatifid, toothed or finely denticulate, always obviously stipulate (save in some Rubieae, where the stipules may be considered foliar or almost absent according to interpretation), the stipules interpetiolar or intrapetiolar, entire or, particularly in herbaceous genera, variously divided into lobes or fimbrieae, often tipped or separated by mucilaginous hairs known as colleters and often with colleters inside the base; the leaves in certain tribes sometimes contain small bacterial nodules Corolla small to large and showy, gamopetalous, rotate to salver-shaped or funnel-shaped, the tube often very long, (3–)4–5(–11)-lobed, the lobes mostly contorted or valvate, sometimes valvate-induplicate, rarely imbricate or quincuncial Stamens usually as many as the corolla-lobes and alternate with them, epipetalous; anthers basi- or dorsifixed, introrse, the thecae rarely multilocellate transversely Pollen various, mostly simple, isopolar and 3-colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some >i>Gardenieae) in tetrads or rarely in polyads Disc often present, 2-lobed or tubular Ovary inferior, rarely half-inferior or (in >i>Gaertnera) superior, syncarpous of 2–5 or more carpels, but predominantly of 2 and therefore predominantly 2-locular, but 3–5 or even 12 or more (e.g. in >i>Urophylleae due to supplementary incomplete partitions); placentation axile or (in some >i>Gardenieae) parietal; ovules 1–many per locule, often embedded in fleshy placentas, erect, basal or horizontal, anatropous; style simple, usually long and narrow, the “stigma” either cylindrical, clavate, or otherwise modified to form a “receptaculum pollinis” or divided into 2–many linear, spathulate or clavate lobes, the actual stigmatic surface sometimes confined to certain areas, e.g. the inner faces of the lobes Fruit small to quite large (0.2–20 cm.), a capsule, berry or drupe or indehiscent or woody, occasionally (e.g. in >i>Nauclea and >i>Morinda) united to form syncarps, (1–)2–many-seeded, if capsules then loculicidal or septicidal or opening by a beak Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; albumen present (save in >i>Guettardeae); embryo straight or rarely curved, the radicle mostly longer than the cotyledons Trees, shrubs, annual or perennial herbs, subshrubs, vines, or lianas, infrequently monocaulous or creeping and rooting at nodes, terrestrial or infrequently epiphytic, with bisexual flowers, infrequently dioecious, or rarely polygamo-dioecious (Diplospora, Galium, Guettarda, perhaps Brachytome) or monoecious (Galium), evergreen or sometimes deciduous (Hymenodictyon), sometimes armed with straight to curved spines (formed by modified stems or peduncles), infrequently with elongated principal stems bearing lateral short shoots (i.e., brachyblasts; Benkara, Catunaregam, Ceriscoides, Himalrandia, Leptodermis, Serissa), infrequently with lateral branches or short shoots spinescent (i.e., prolonged, sharp, and leafless at apex), infrequently with reduced internodes that give an appearance of verticillate leaf arrangement (Brachytome, Damnacanthus, Duperrea, Rothmannia, Rubovietnamia), infrequently with buds resinous (Gardenia) or mucilaginous (Scyphiphora), infrequently with tissues fetid when bruised, [rarely with swollen hollow stems or leaf bases housing ants (Neonauclea)]; branchlets terete to angled or quadrate, in latter two cases often becoming terete with age, or rarely flattened (Wendlandia) or winged (Hedyotis, Rubia), buds conical or rounded with stipules valvate or imbricate, or infrequently flattened with stipules erect and pressed together (Cinchona, Haldina, Nauclea, Neonauclea). Raphides present or absent. Leaves opposite, verticillate, or apparently verticillate (i.e., closely set due to reduced internodes), decussate or occasionally distichous, petiolate to sessile, infrequently somewhat to strongly anisophyllous, rarely punctate- or striate-glandular (Galium); margins flat to occasionally undulate or crisped, entire or rarely lobed (Hymenodictyon, Morinda) to denticulate or serrate (Hymenodictyon, Leptomischus, Ophiorrhiza, Wendlandia); secondary veins pinnate or rarely triplinerved or palmate (Hedyotis, Rubia), free (i.e., eucamptodromous) or uniting near margins (i.e., brochidodromous) in weak to well-developed or rarely substraight submarginal vein, sometimes with foveolate (i.e., pitted or cryptlike) and/or tufted (i.e., pubescent) domatia (i.e., structures that house mites) in abaxial axils, these rarely also present in axils of tertiary veins (Morinda), with presence of domatia often variable within a species; tertiary and/or quaternary venation rarely arranged in regular squares (Guettarda), regular rectangles (i.e., clathrate; Urophyllum), or lineolate (i.e., closely parallel within each areole; Timonius); petiole rarely articulate at base (Ixora); stipules persistent with leaves, deciduous before leaves, or quickly caducous, interpetiolar and infrequently fused to adjacent petioles or leaf bases, sometimes united around stem into a sheath, rarely completely united into a conical cap (i.e., calyptrate; Gardenia), with interpetiolar portion variously triangular in general shape to truncate, with apex entire or bilobed, multifid, lacerate, setose, or laterally appendaged, with apex, lobes, setae, and/or appendages sometimes glandular (Chassalia, Hedyotis, Hymenodictyon, Knoxia, Mitchella, Mycetia, Neanotis, Ophiorrhiza, Pentas, Pseudopyxis, Psychotria, Trailliaedoxa), internally (i.e., adaxially) with small to well-developed colleters (i.e., glandular trichomes), these infrequently persistent after stipules fall (Psychotria), or stipules rarely expanded into 1 to several leaflike segments and then apparently absent due to leaflike form that gives an appearance of verticillate leaves (Argostemma, Asperula, Galium<General Information
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Morphology
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Habitat
\rLes Rubiaceae ont rarement pu s'adapter aux climats désertiques (Gaillonia) ou tempérés (Rubia, Galium, Asperula). Certaines hautes montagnes d'Afrique recèlent les genres paléarc-tiques Rubia et Galium.
\rL'épiphytisme est rare; il se rencontre en Asie chez Myrme-codia, Hymenopogon, Hydnophytum, et en Amérique chez Hillia pour ne citer que les genres les plus remarquables. En Afrique un Hymenodictyon et un Psychotria sont par exception des épiphytes.Source: [
Flore du Gabon
Morphology
\rLes Rubiaceae ont rarement pu s'adapter aux climats désertiques (Gaillonia) ou tempérés (Rubia, Galium, Asperula). Certaines hautes montagnes d'Afrique recèlent les genres paléarc-tiques Rubia et Galium.
\rL'épiphytisme est rare; il se rencontre en Asie chez Myrme-codia, Hymenopogon, Hydnophytum, et en Amérique chez Hillia pour ne citer que les genres les plus remarquables. En Afrique un Hymenodictyon et un Psychotria sont par exception des épiphytes.Flora of West Tropical Africa - species descriptions
MorphologyFlora Zambesiaca - descriptions
MorphologyNortheastern Flora
General InformationPlants Of the World Online Portal - FTEA
MorphologyFlora of China @ efloras.org
General Information
