The World Flora Online

Seed without endosperm; embryo straight with plano-convex cotyledons Fruit (achene) sessile, sometimes beaked Stamens 5, rarely 4, epipetalous; filaments free; anthers connate into a tube, rarely free, 2-locular, opening lengthwise, often appendaged at the apex and tailed at the base Ovary inferior, 1-locular, 1-ovuled; style of the hermaphrodite or female florets mostly 2-fid, the style-arms smooth, papillose or hairy, tapered, rounded, deltoid or truncate, with or without a terminal appendage Calyx epigynous, reduced to a pappus of persistent or caducous hairs, bristles or scales, or absent Corolla sympetalous, 4-5-fid (actinomorphic disk-florets), filiform, ligulate or rarely bilabiate (zygomorphic ray-florets) Ovule erect from the base Flowers (florets) crowded into heads (capitula) surrounded by an involucre of one or more series of free or connate bracts; sometimes the heads compound with the capitula few- or single-flowered; receptacle paleate, setose, pitted or naked, usually convex, sometimes elongated or concave Florets of one or two kinds in each capitulum, hermaphrodite, unisexual or neuter, rarely dioecious, the outer ones often ligulate (ray-florets), the inner ones tubular (disk-florets), or all tubular, or all ligulate Herbs, shrubs or rarely small trees or climbers Leaves alternate or opposite, simple or variously divided; stipules absent Fruit (achene) sessile, sometimes beaked Stamens 5, rarely 4, epipetalous; filaments free; anthers connate into a tube, rarely free, 2-locular, opening lengthwise, often appendaged at the apex and tailed at the base Ovary inferior, 1-locular, 1-ovuled; style of the hermaphrodite or female florets mostly 2-fid, the style-arms smooth, papillose or hairy, tapered, rounded, deltoid or truncate, with or without a terminal appendage Calyx epigynous, reduced to a pappus of persistent or caducous hairs, bristles or scales, or absent Corolla sympetalous, 4-5-fid (actinomorphic disk-florets), filiform, ligulate or rarely bilabiate (zygomorphic ray-florets) Ovule erect from the base Flowers (florets) crowded into heads (capitula) surrounded by an involucre of one or more series of free or connate bracts; sometimes the heads compound with the capitula few- or single-flowered; receptacle paleate, setose, pitted or naked, usually convex, sometimes elongated or concave Florets of one or two kinds in each capitulum, hermaphrodite, unisexual or neuter, rarely dioecious, the outer ones often ligulate (ray-florets), the inner ones tubular (disk-florets), or all tubular, or all ligulate Herbs, shrubs or rarely small trees or climbers Leaves alternate or opposite, simple or variously divided; stipules absent

Capitula solitary and terminal on scapes or leafy stems, or few to very numerous in lax or ± clustered cymose, often corymbiform synflorescences, occasionally scorpioidly cymose (a reduced cymose arrangement in which the subtending bracts are alternate), or spicate, racemose or paniculate, or aggregated into secondary capitula (glomerules) Common receptacle with scales (paleae) or setae subtending the florets, or epaleate and the surface smooth areolate or shallowly to deeply honeycombed (alveolate); alveolae often fimbriate or setose Phyllaries in 2-many series, free and imbricate or ± connate, or sometimes 1-seriate and united or with cohering overlapping margins, persistent or rarely caducous, occasionally accrescent, sometimes apically appendaged Flowers (florets) small, 1–500 or more per capitulum, hermaphrodite or unisexual (female, male or functionally male), or neuter (sterile); ovary inferior, of 2 united carpels, unilocular with 1 erect basal ovule; perianth epigynous Calyx absent, represented by the pappus borne apically on the ovary; pappus consisting of persistent or caducous, 1 -many-seriate hairs bristles awns or scales, or pappus elements ± fused to form an annular or ± cup-shaped or ear-shaped corona, or pappus absent; pappus setae barbellate or ± plumose Corolla gamopetalous, of(3-)5 united petals, rarely absent; corolla ± regular and (3-)5-lobed (filiform or infundibuliform disk-florets), or bilabiate with a 2-lobed inner lip and a 3-dentate outer lip, or radiate with an abaxial strap-shaped limb (ray) 0–3(4)-dentate at the apex (ray-florets), or ligulate with a strap-shaped limb (ligule) 5-dentate at the apex Style of hermaphrodite or functionally male florets elongating within the anther tube, shallowly to deeply bifid, occasionally undivided in functionally male florets, style arms with stigmatic areas on their inner sides and acute rounded or truncate at the apex, or the arms produced beyond the stigmatic surfaces as triangular, subulate or clavate appendages, variously papillate or hairy, usually with a brush of collecting hairs that sweep the pollen from the anther tube; style of female florets simpler, with acute to rounded style arms and without sweeping hairs Stamens (3-)5, filaments free, inserted on the corolla tube, contractile; anthers introrse, usually apically appendaged, usually laterally connate into a cylinder around the style, thecae rounded sagittate or tailed at the base; pollen usually echinate, sometimes echinolophate or lophate The floret sexual state, its corolla form, and the combination of floret types on the common receptacle distinguish capitula as follows:Capitula homogamous discoid - all florets of one sexual state, all hermaphrodite (or all female or functionally male); all corollas of the same form and ± regular Fruit unilocular, 1-seeded, indehiscent (usually an achene), rarely fleshy with the single seed enclosed in a hard endocarp (drupe), sometimes produced apically into a beak (rostrum), crowned by the persistent or caducous pappus, or epappose; endosperm absent or vestigial Capitula heterogamous disciform - florets of 2(3) sexual states, the inner florets hermaphrodite or functionally male and the outer ones filiform and female; all corollas regular Capitula heterogamous radiant - inner florets hermaphrodite or functionally male, marginal florets larger and neuter; all corollas regular Capitula homogamous ligulate - all florets hermaphrodite; all corollas ligulate Capitula heterogamous radiate - central florets hermaphrodite or female or functionally male, outer florets female or neuter, occasionally hermaphrodite; central floret corollas regular, outer or marginal floret corollas radiate, or occasionally bilabiate with a strap-shaped outer lip Capitula heterogamous bilabiate - inner florets functionally male, outer florets female; corollas bilabiate, in the Flora Zambesiaca area the inner corollas are all equally 2-lipped, while the outer corollas are of 2 kinds, i) 2–3 series of submarginal corollas equally 2-lipped, ii) a marginal series in which the corolla outer lip is strap-shaped (apparently radiate) and the inner lip smaller and 2-lobed (eg. Gerbera, Tab. 9). Occasionally all florets male or all female (plants monoecious or dioecious), or the disk-florets functionally female and the ray-florets functionally male Inflorescence a capitulum with individual flowers ± sessile and aggregated on a common receptacle and surrounded by an involucre of 1-many series of bracts (phyllaries) Leaves cauline and alternate or opposite, sometimes whorled, or radical and rosulate, exstipulate or sometimes with stipuliform appendages, sessile or petiolate, usually simple, entire, toothed, lobed or variously dissected Annual, biennial or perennial herbs (often suffrutescent in the Flora Zambesiaca area with annual leafy stems or scapes from woody rootstocks and/or root tubers), or subshrubs, shrubs, or occasionally scramblers or lianes, sometimes trees, rarely aquatic or epiphytic, sometimes succulent, sometimes spinescent; tissues with schizogenous resin-ducts or articulated lacticifers Common receptacle with scales (paleae) or setae subtending the florets, or epaleate and the surface smooth areolate or shallowly to deeply honeycombed (alveolate); alveolae often fimbriate or setose Phyllaries in 2-many series, free and imbricate or ± connate, or sometimes 1-seriate and united or with cohering overlapping margins, persistent or rarely caducous, occasionally accrescent, sometimes apically appendaged Flowers (florets) small, 1–500 or more per capitulum, hermaphrodite or unisexual (female, male or functionally male), or neuter (sterile); ovary inferior, of 2 united carpels, unilocular with 1 erect basal ovule; perianth epigynous Calyx absent, represented by the pappus borne apically on the ovary; pappus consisting of persistent or caducous, 1 -many-seriate hairs bristles awns or scales, or pappus elements ± fused to form an annular or ± cup-shaped or ear-shaped corona, or pappus absent; pappus setae barbellate or ± plumose Corolla gamopetalous, of(3-)5 united petals, rarely absent; corolla ± regular and (3-)5-lobed (filiform or infundibuliform disk-florets), or bilabiate with a 2-lobed inner lip and a 3-dentate outer lip, or radiate with an abaxial strap-shaped limb (ray) 0–3(4)-dentate at the apex (ray-florets), or ligulate with a strap-shaped limb (ligule) 5-dentate at the apex Style of hermaphrodite or functionally male florets elongating within the anther tube, shallowly to deeply bifid, occasionally undivided in functionally male florets, style arms with stigmatic areas on their inner sides and acute rounded or truncate at the apex, or the arms produced beyond the stigmatic surfaces as triangular, subulate or clavate appendages, variously papillate or hairy, usually with a brush of collecting hairs that sweep the pollen from the anther tube; style of female florets simpler, with acute to rounded style arms and without sweeping hairs Stamens (3-)5, filaments free, inserted on the corolla tube, contractile; anthers introrse, usually apically appendaged, usually laterally connate into a cylinder around the style, thecae rounded sagittate or tailed at the base; pollen usually echinate, sometimes echinolophate or lophate The floret sexual state, its corolla form, and the combination of floret types on the common receptacle distinguish capitula as follows:Capitula homogamous discoid - all florets of one sexual state, all hermaphrodite (or all female or functionally male); all corollas of the same form and ± regular Fruit unilocular, 1-seeded, indehiscent (usually an achene), rarely fleshy with the single seed enclosed in a hard endocarp (drupe), sometimes produced apically into a beak (rostrum), crowned by the persistent or caducous pappus, or epappose; endosperm absent or vestigial Capitula heterogamous disciform - florets of 2(3) sexual states, the inner florets hermaphrodite or functionally male and the outer ones filiform and female; all corollas regular Capitula heterogamous radiant - inner florets hermaphrodite or functionally male, marginal florets larger and neuter; all corollas regular Capitula homogamous ligulate - all florets hermaphrodite; all corollas ligulate Capitula heterogamous radiate - central florets hermaphrodite or female or functionally male, outer florets female or neuter, occasionally hermaphrodite; central floret corollas regular, outer or marginal floret corollas radiate, or occasionally bilabiate with a strap-shaped outer lip Capitula heterogamous bilabiate - inner florets functionally male, outer florets female; corollas bilabiate, in the Flora Zambesiaca area the inner corollas are all equally 2-lipped, while the outer corollas are of 2 kinds, i) 2–3 series of submarginal corollas equally 2-lipped, ii) a marginal series in which the corolla outer lip is strap-shaped (apparently radiate) and the inner lip smaller and 2-lobed (eg. Gerbera, Tab. 9). Occasionally all florets male or all female (plants monoecious or dioecious), or the disk-florets functionally female and the ray-florets functionally male Inflorescence a capitulum with individual flowers ± sessile and aggregated on a common receptacle and surrounded by an involucre of 1-many series of bracts (phyllaries) Leaves cauline and alternate or opposite, sometimes whorled, or radical and rosulate, exstipulate or sometimes with stipuliform appendages, sessile or petiolate, usually simple, entire, toothed, lobed or variously dissected Annual, biennial or perennial herbs (often suffrutescent in the Flora Zambesiaca area with annual leafy stems or scapes from woody rootstocks and/or root tubers), or subshrubs, shrubs, or occasionally scramblers or lianes, sometimes trees, rarely aquatic or epiphytic, sometimes succulent, sometimes spinescent; tissues with schizogenous resin-ducts or articulated lacticifers

Individual fls epigynous, perfect or unisexual, sympetalous, regular or irregular, commonly 5- merous, without definite cal; stamens alternate with the cor-lobes, epipetalous, usually with elongate anthers united into a tube; ovary bicarpellate but unilocular, with a single erect ovule; style usually 2-cleft; fr an achene, unappendaged, or more commonly crowned with a pappus consisting of hairs or scales; fls sessile in a close head on a common receptacle, sometimes individually subtended by a small bract (chaff), and almost always collectively subtended by an invol of few to many bracts; our spp. annual to perennial herbs or rarely shrubs, the heads arranged in various sorts of basically determinate infls. (Compositae, nom. altern.) 1100/20,000. The invol bracts are usually herbaceous or subherbaceous in texture, varying to scarious, hyaline, coriaceous, or cartilaginous. They may be few and in a single row, or numerous and imbricate, or modified into spines, or even (as in Xanthium) concrescent into a bur.The receptacle may be chaffy, with a bract behind each fl (as in many Heliantheae), or may be covered with long, stout bristles (as in most Cynareae), or may be naked, without chaff or bristles. When naked it may sometimes be minutely pitted, with slender, chaffy partitions separating the pits, and is then said to be alveolate. It may even be softly hairy, as in some spp. of Artemisia.The fls are of several general types. In one type they are perfect (or functionally staminate) and the cor is tubular or trumpet-shaped or goblet-shaped, with typically 5 short lobes or teeth. This type of fl is called a disk-fl. A head composed wholly of disk-fls is said to be discoid.In another type the fl is pistillate or neutral (without a style), and the cor is tubular only at the very base, above which it is flat and usually bent backward so as to spread away from the center of the head. The flattened part of a cor of this type is called a ray or ligule, and the fl bearing it is called a ray-fl or ligulate fl. Often the ligules exhibit traces of 2 or 3 cor-lobes as small terminal teeth. Except for the pistillate heads of a few dioecious groups, the head is never composed wholly of fls of this type. Instead these pistillate or neutral ray-fls are found at the margin of the head, the center being occupied by the disk-fls. Such a head, with both ray-fls and disk-fls, is said to be radiate.In some spp. the ray or ligule of the marginal, pistillate fls does not develop, so that the cor is tubular. In addition to not bearing stamens, a cor of this type differs from the cor of an ordinary disk-fl in the absence of the regular terminal teeth, and often also in being more slender. A head in which the pistillate fls lack rays is said to be disciform, although the term discoid is sometimes loosely extended to cover this type.Another type of fl superficially resembles the ray-fl of a radiate head, but differs in being perfect and in usually having 5 terminal teeth on the ligule. The heads of the tribe Lactuceae consist wholly of fls of this type and are called ligulate heads. Ligulate perfect fls are rare in other tribes, and almost never make up the whole head.In some spp. of Centaurea the marginal fls are neutral and have an enlarged, irregular, ray-like cor. These fls are considered to be modified disk-fls. Members of the tribe Mutisieae (not represented in our region) usually have some fls with a bilabiate cor.The pollen-presentation mechanism is a characteristic feature of the family. The anthers are coherent by their lateral margins, or rarely merely connivent. The base of the anther varies from obtuse or subtruncate to broadly rounded, sagittate, or distinctly caudate (tailed). The anthers dehisce introrsely, and the pollen is pushed out through the anther-tube by growth of the style. The style-branches commonly diverge above the anther-tube, have various distinctive forms and texture, and tend to be stigmatic only on limited parts of their surface. The characteristic style- branches of the various tribes are to be sought only in the fertile disk-fls. The styles of ray-fls are mostly very similar in all groups, and those of sterile disk-fls are often reduced and undivided. The sterile disk-fls, when present, are said to be functionally staminate. Strictly staminate fls, with no pistillate parts, do not normally occur in the Asteraceae, because the style is necessary as a piston or plunger to eject the pollen.