Sago-palm family (Landry 1993).
A family of eight genera and about 100 species, subdivided as follows:
Plants perennial, evergreen, dioecious. Stems subterranean with exposed apex or aboveground, fleshy, stout, cylindric, simple or irregularly branched. Roots with small secondary roots; coral-like roots developing at base of stem at or below soil surface. Leaves pinnately compound, spirally clustered at stem apex, leathery; leaflets entire, dentate or spinose, venation dichotomous or netted; resin canals absent. Cones axillary, appearing terminal, short-peduncled or sessile, disintegrating at maturity; sporophylls densely crowded, spirally arranged. Pollen cones soon shed, generally smaller and more numerous than seed cones; sporophylls bearing many crowded, small microsporangia (pollen sacs) adaxially; pollen spheric. Seed cones persisting a year or more, 1(2) per plant, nearly globose to ovoid, tapering sharply or blunt at apex; sporophylls peltate, thickened and laterally expanded distally, bearing 2(3) ovules. Seeds angular, inner coat hardened, outer coat fleshy, often brightly colored; cotyledons 2 (Landry 1993).
Australia (Chigua, Lepidozamia, Macrozamia), Neotropics (Georgia to Bolivia) (Ceratozamia, Dioon, Microcycas, Zamia) and sub-Saharan Africa (Encephalartos). All species occupy subtropical or tropical habitats, with precipitation regimes ranging from the semiarid to swamps or tropical rainforests (Jones 1993).
de Candolle, A.L.P. 1868. Cycadaceae. In: A. P. de Candolle and A. L. P. de Candolle, eds. 1823-1873. Prodromus Systematis Naturalis Regni Vegetabilis.... Paris etc. Vol. 16, part 2, pp. 522-547.
Johnson, L.A.S. 1959. The families of cycads and the Zamiaceae of Australia. Proceedings of the Linnean Society of New South Wales 84: 64-117.
Osborne, R., A. Salatino, M.L.F. Salatino, C.M. Sekiya, and M. Vasquez-Torres. 1993. Alkanes of foliar epicuticular waxes from five cycad genera in the Zamiaceae. Phytochemistry 33: 607-609. Abstract: The n-alkane distribution patterns from 31 specimens in the meso-American cycad genera Ceratozamia, Dioon, Zamia and two Australian taxa, reported from GC analysis, complement a previously published investigation of the African genus, Encephalartos and complete a survey of the Zamiaceae. The significant proportions of n-alkane homologues with short ( lt n-C-25) carbon chains, the extended distribution range (n-C- 26 to n-C-33) and a general absence of prevalence of odd- over even-numbered homologues collectively provides evidence for a monophyletic origin of the Zamiaceae and distinguishes the cycads chemotaxonomically from other gymnosperms and from angiosperms. Exceptions to the general trend are seen in Dioon califanoi, which shows an angiosperm-like bias towards odd- numbered carbon alkanes, and to a lesser extent in two species of Ceratozamia and three of Zamia. Alkane distribution profiles do not allow any distinction between the genera of the Zamiaceae and show little species specificity.
Schuster, J. 1932. Cycadaceae. Vol. 99[IV,1], pp. l-168 in H.G.A. Engler, ed., 1900-1953. Berlin: Das Pflanzenreich.... .
Last Modified 2017-12-29