Ceratozamia robusta Miq.

국표에 없다.

Origin and Habitat: The genus Ceratozamia contains 16-18 currently living species and one or two fossil species. Most species are endemic to mountainous areas of Mexico, while Ceratozamia robustaSN|30191]]SN|30191]] extends into the mountains of Guatemala and Belize. However, local experts believe that there are at least six to seven taxa currently identified as Ceratozamia robustaSN|30191]]SN|30191]]. Most of the populations are small with less than 30 plants.
Habitat and Ecology: Plants occur as an understorey plant in evergreen wet, humid tropical forests. Usually in limestone areas on steep slopes and cliffs. Though it is distributed in various localities within the Mexican states of Veracruz, Oaxaca, and Chiapas as well as Guatemala and Belize, nearly all of the populations show continued declines, almost entirely due to habitat destruction (clearing) and fires. Moreover many specimens have been collected in the past for ornamental purposes.

Common Names include:
SPANISH (Español): Costilla De León

Description: Ceratozamia robustaSN|30174]]SN|30191]] is the largest of the ceratozamias and can attain a spread of 5-6 or more metres with usually branched upright or procumbent stems up to 2 metres tall. On its top it carries a tuft consisting of long arcing fronds, that are spirally arranged and interspersed with cataphylls (Modified leaf, much reduced and thickened, serving to protect the apical meristem and produced in flushes preceding the emergence of cones or leaves). The individual plants are either all male or all female (dioecious). C. robusta is widely distributed over a large area and variations occur in leaflet width and length growth. The taxonomy of this taxon is uncertain and many subpopulations may in future be classified as separate species.

Derivation of specific name: Latin, robusta, large.
Distinguishing characters: C. robusta is a large palm-like plant with long leaves and thick wide leaflets with densely prickled petioles and the prickles are stout. Microsporophyll apex with prominent paired horn-like projections are also characteristic of this species and are placed in vertical rows in cones.
Stems: Partially subterranean, pachycaul, dark brown, erect, bent or procumbent up to 200 cm long, and up to 30 cm in diameter.
Roots: In this plant the coral-roots appear, as in Cycas, often in great numbers. Coralloid roots are special upwardly growing multi-branched roots where nitrogen is fixed in symbiosis with Nostoc and Anabena algae. They differ from the ordinary soil-roots by their forked branching.
Leaves (fronds): 5-35 in crown, pinnate, arching, 2-3 m long, flat (not keeled) in section, bright green, semiglossy, new growth emerging bronze, red or chocolate brown, or mid-green, smooth, and glabrous. Leaflets 50-200, simple, entire, not clustered, symmetric, broadest below middle, falcate, light green above, paler beneath, articulated, inserted near the edges of the rachis towards the adaxial side with numerous parallel veins and no distinct midrib. Blades lanceolate, coriaceous to almost papery, around 25-30 cm in length, 2.5-4(-5) cm wide, apex acute, the margins rolled back, lower leaflets not reduced to spines. Rachis not or slightly spirally twisted. Petioles 20-60 cm long, swollen and woolly at the base, densely prickled and the prickles are stout.
Pollen Cones: Cylindrical to conical, greenish to brown, 30-40(-50) cm long, 10-14 cm in diameter, microsporophylls 3-5 mm long, each with a pair of recurved horns. Peduncle c. 10 cm long, woolly.
Seed Cones: Ovoid-cylindrical, bluish-green (25-)30-40(-50) cm long, 10-15 cm wide, megasporophylls broadly exagonal, 3-3.5 cm long, each with a pair of recurved horns. Peduncle c 15 cm long, woolly. Female cone splits open at maturity.
Seeds: Ovoidal, 25(-30) mm long, 20 mm wide, creamy white becoming brown as they ages.
Note: C. robusta has been included with Ceratozamia mexicanaSN|30191]]SN|30174]] by some authorities but is much more vigorous with a larger trunk, longer leaves and cones and acute tips on the leaflets. Plants from the forests of Belize and Guatemala are the largest of all and often have crowns of relatively lax leaves. Those from Veracruz are smaller and less vigorous than other variants and those from Chiapas fall somewhere in between"

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