The World Flora Online

Plantes ligneuses , dioïques, à port de palmier, à racines tubéreuses et munies de nodosités; tronc généralement simple, épais, écailleux ou non, surmonté d'une couronne de grandes feuilles spiralées, pennées ou parfois bipennées, à moelle abondante et canaux gommifères.'Strobiles'grands, à sporophylles spiralés et nus.'Écailles staminales'portant sur leur face inférieure de nombreux sacs polliniques groupés par 2-6; anthérozoïdes ciliés.'Écailles ovulifères'généralement peltées et portant à leur base interne 2 ovules, parfois pennées et à 4-10 ovules latéraux; ovules orthotropes et unitégumentés.'Graines drupacées (fausses drupes), à enveloppe externe charnue et à noyau dur, à endosperme abondant et amylacé et à embryon droit.\n\t\t\tActuellement 9 genres et 65 espèces dans les régions tropicales et subtropicales; famille mieux représentée autrefois, du Carbonifère supérieur au Jurassique inférieur. Plusieurs espèces sont ornementales; certains'Cycas'et'Encephalartos donnent du Sagou (moelle de la tige).

Males terminal or subterminal, composed of numerous leathery or fleshy flat or peltate scales bearing on the under-surface numerous pollen-sacs Cones dioecious Shrubs or small trees with thick, usually simple stems and a crown of pinnatisect leaves circinate in bud; leaflets often with spiny teeth Female cones similar, the scales bearing a pair of inverted nude ovules on the lower side Seeds large, drupe-like, with copious endosperm; cotyledons 2 Cones dioecious Shrubs or small trees with thick, usually simple stems and a crown of pinnatisect leaves circinate in bud; leaflets often with spiny teeth Female cones similar, the scales bearing a pair of inverted nude ovules on the lower side Seeds large, drupe-like, with copious endosperm; cotyledons 2

Staminate strobilus forming a terminal cone of leathery scales with numerous pollen-sacs on their abaxial surface Leaves usually long and pinnate, in close spirals, forming an often wide-spreading crown on the trunk and (except in one species of Macrozamia) intercalated with leathery scale-leaves Female strobilus either a loose apical whorl of fronds bearing erect ovules marginally (Cycas) or a terminal cone of thick and often woody scales bearing a pair of inverted ovules adaxially Trunk simple or sparsely branched, covered with spirally arranged leaf-bases and scale-leaves, either up to 15 m. tall or very short and almost subterranean Dioecious trees or shrubs Leaves usually long and pinnate, in close spirals, forming an often wide-spreading crown on the trunk and (except in one species of Macrozamia) intercalated with leathery scale-leaves Female strobilus either a loose apical whorl of fronds bearing erect ovules marginally (Cycas) or a terminal cone of thick and often woody scales bearing a pair of inverted ovules adaxially Trunk simple or sparsely branched, covered with spirally arranged leaf-bases and scale-leaves, either up to 15 m. tall or very short and almost subterranean Dioecious trees or shrubs

Trees or shrubs evergreen, dioecious, mostly palmlike; trunk columnar, sometimes dichotomously branched at apex, rarely ovoid-bulbous and subterranean, clothed with bases of fallen leaves; bark often thickened and roughened. Leaves borne at apex of trunk, 1(-3)-pinnately compound, spirally arranged; new leaves erect (or somewhat inflexed and appearing coiled in C. multipinnata group), with circinnate leaflets; petiole with spines representing (reduced basal leaflets), rarely unarmed, base swollen and hairy; leaflets numerous, alternate to subopposite, dichotomously branched in a few species, midvein present, margin usually entire. Cataphylls prominent, alternate with leaves, hairy, apex often rigid and pungent. Pollen cones borne at apex of trunk, cylindric or fusiform; microsporophylls numerous, scalelike, spirally and tightly arranged along axis of cone, with numerous microsporangia in groups abaxially; pollen tubes producing 2 motile sperm cells. Megasporophylls several to numerous, somewhat leaflike, alternating with flushes of leaves, arranged in a loose, "conelike" crown surrounding apex of trunk, each with a linear fertile stalk and an apical, pinnatifid or subentire sterile blade; ovules (1 or)2-5 on each side of stalk. Seeds drupelike, somewhat compressed; seed coat 3-layered, consisting of colored sarcotesta, woody sclerotesta, and membranous endotesta. Cotyledons 2, united at base. Germination hypogeal, cryptocotylar. 2n = 22*.