Ceratozamia range map (1).

Ceratozamia Brongniart 1846

Common Names

Taxonomic notes

"Although at this stage there is no formal infrageneric classification, studies by researchers at the New York Botanical Garden, USA, University of Naples, Italy, and the University of Veracruz, Mexico, have shown the existence of two groups within the genus. ... Group 1 includes C. euryphyllidia. C. hildae, C. latifolia, C. microstrobila and C. miqueliana. Members of this group have small cones and relatively broad, thin-textured to almost papery leaflets which are developed in a strongly asymmetrical manner, taper gradually to the base and abruptly to the acuminate apex. Group 2 includes C. kuesteriana, C. matudae, C. mexicana, C. norstogii, C. robusta and C. zaragozae. Members of this group have small to large cones and the leaflets of mature plants are narrow, thin-textured to thick and leathery, are symmetrical or almost symmetrical, do not taper noticeably to the base and the apex may be drawn out or acute.

"The genus Ceratozamia has been well studied in recent times and no major changes in taxonomy are expected" (1). A recent detailed treatment is presented in (2).

Description

"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:

  • "stipules present, at least in seedlings;
  • "pinnate leaves borne in whorls;
  • "leaf bases deciduous;
  • "leaflets articulate;
  • "trichomes with an oblong basal cell: and
  • "spinose prickles on the petiole and rhachis (in some species these prickles may be much reduced or are extremely sparse)" (1).

Range

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 (1).

"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)" (1).

Big Tree

C. robusta.

Oldest

Dendrochronology

Ethnobotany

All species are at least occasionally used as ornamentals (1).

Observations

Remarks

"Species of Ceratozamia have suffered at the hands of poachers and all are included on Appendix 1 of CITES" (1).

Ceratozamia is first known from leaf fragments in Eocene deposits on Kupreanof Island, Alaska (1).

"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)" (1).

The following Key is quoted from Jones, Cycads of the World (1):

KEY TO SPECIES


Adapted from Stevenson, Sabato and Vazquez-Torres, Brittonia 38 (1986):17-26. C. sabatoi not yet included.
1
 		Rhachis spirally twisted
Rhachis not spirally twisted		2
3
2
 		Leaves to 2 m long, leaflets to 50 cm long
Leaves to 1 m long, leaflets to 25 cm long		C. norstogii
C. zaragozae
3
 		Leaflets arranged in clusters
Leaflets arranged evenly along the rhachis		C. hildae
4
4
 		Leaflets widest above the middle
Leaflets widest at or below the middle		5
8
5
 		Leaflets >5 cm wide
Leaflets <5 cm wide		7
6
6
 		 Leaflets to 4 cm wide
Leaflets to 3 cm wide		C. latifolia
C. microstrobila
7
 		 Leaflets 5-8 cm wide, papery, margins flat
Leaflets 9-16 cm wide, translucent, margins wavy		C. miqueliana
C. euryphyllidia
8
 		 Leaflets >1.5 cm wide, margins flat
Leaflets <1.5 cm wide, margins revolute		9
10
9
 		 Leaflets <2.5 cm wide, straight to slightly falcate
Leaflets more than 2.5 cm wide, strongly falcate		C. mexicana
C. robusta
10
 		 Petiole and rhachis smooth or sparsely prickly
Petiole and rhachis with numerous stout prickles		C. kuesteriana
C. matudae

Citations

(1) Jones 1993.

(2) D. Stevenson, 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.

See also:

Jeffrey Chemnick, Timothy J. Gregory and Morales S. Salas. 1997. Ceratozamia mixeorum (Zamiaceae), a new species from Oaxaca, Mexico with comments on distribution, habitat, and species relationships. Phytologia 83: 47-52.

Mario Vazquez-Torres and Andrew P. Vovides. 1998. A new species of Ceratozamia (Zamiaceae) from Veracruz, Mexico. Novon 8: 87-90.

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This page is from the Gymnosperm Database
URL: http://www.geocities.com/~earlecj/za/ce/index.htm
Edited by Christopher J. Earle
E-mail:earlecj@earthlink.com
Last modified on 18-Dec-1999

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