Ceratozamia mexicana [C.J. Earle].
Distribution of Ceratozamia species (redrawn from Jones 1993).
Ceratozamia
The scientific name translates as "horncone."
A genus of 38 species:
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For species not described here, please refer to The World List of Cycads.
The systematics of the genus have been presented by Stevenson et al. (1986) and by Vovides et al. (2004). The latter authors identify several species complexes associated with Pleistocene floristic refugia, with subsequent radiation northwards, perhaps accompanied by rapid speciation.
"Terrestrial cycads with a relatively slender, ovoid or cylindrical, rarely branched trunk which may be partly subterranean and partly emergent or wholly emergent. Leaf bases falling free at senescence. New leaves emerging in flushes, green or copper coloured, glabrous or hairy. Mature leaves pinnate, oblong or lanceolate in outline, straight, mostly flat in cross-section. Petioles swollen at the base, hairy, bearing prickles although in some species these are extremely sparse or absent. Rhachis straight or twisted, bearing prickles or unarmed. Leaflets articulate at the base, opposite to nearly opposite, evenly spaced or in clusters, straight or falcate, entire, margins flat, involute or revolute; veins prominent or immersed and obscure. Male cones one or two, cylindrical, erect, hairy, pedunculate; sporophylls usually with two prominent spine-like horns, those on the female cones longer and stouter than the male. Female cones generally solitary, ovoid, shortly hairy; sporophylls with two prominent spine-like horns. Seeds radiospermic, ovoid to subglobose, the sarcotesta cream to whitish.
"Species of Ceratozamia share many characters with the genus Zamia but all species of Ceratozamia can be immediately distinguished by the paired, horn-like projections on the peltate sporophylls. Other useful generic features include:
Mexico, Belize and Guatemala. Most species are found at elevations of 800 to 1800 m in cloud forests in the mountains of Mexico, with a couple of widely distributed species extending farther south and to low elevations. Populations are distributed in a relatively narrow band that more or less parallels the mountain systems of the region (Jones 1993).
"Vegetation types range from the almost constantly wet tropical rainforests to less wet broad-leaved forests and to drier types which contain a mixture of pines and oaks and have a pronounced seasonal wet-dry regime. Researchers have noted strong correlations between species in factors such as leaflet width and texture and the wetness of the habitat (broad, thin-textured leaves in wet habitats versus narrow or inrolled, leathery leaves in drier habitats)" (Jones 1993).
The largest individuals are in Ceratozamia robusta.
All species are at least occasionally used as ornamentals (Jones 1993).
"Species of Ceratozamia have suffered at the hands of poachers and all are included on Appendix 1 of CITES" (Jones 1993).
Ceratozamia is first known from leaf fragments in Eocene deposits on Kupreanof Island, Alaska (Jones 1993).
"The generic name refers to the paired, horn-like projections which are found on the male and female sporophylls of all species (Greek ceras, 'horn'; Zamia, the name of another genus)" (Jones 1993).
Stevenson, D., S. Sabato and M. Vazquez-Torres. 1986. A new species of Ceratozamia (Zamiaceae) from Veracruz, Mexico with comments on species relationships, habitats, and vegetative morphology in Ceratozamia. Brittonia 38: 17-26.
Vovides, A.P., D. Gonzalez, M.A. Pérez-Farrera, S. Avedano, and C. Barcenas. 2004. A review of research on the cycad genus Ceratozamia Brongn. (Zamiaceae) in Mexico. Taxon 53(2):291-297.
Last Modified 2023-03-03
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