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Accepted Scientific Name: Ceratozamia mexicana Brongn.
Ann. Sci. Nat., Bot. sér. 3, 5: 8 (1846)
Leaves at Cycad International, Katherine, Northern Territory, Australia. 09-03-2005
Origin and Habitat: Ceratozamia mexicana is indigenous to central Mexico (Hidalgo, Puebla, San Luis Potosí, Querétaro and Veracruz states) and is found widely distributed from low to moderate elevations. This species is known from six localities. Demographic studies at one of the localities in Coacoazintla (Veracruz state) indicate that the local population may exceed 500,000 individuals. It is cultivated as an ornamental in other warm areas or as a tub plant. The plant is cultivated in glasshouses, too.
Habitat and Ecology: Plants are widely distributed from low to moderate elevations and are found in areas ranging from evergreen tropical forests to cloud or mist forests and mixed deciduous woodlands and a range of geological substrates. Typically found in rocky hills. Sometime it forms an almost impenetrable understorey that inhibits regeneration of other species. The mountain cloud forest habitat is threatened by habitat destruction. Forest is cleared for agriculture and cattle farming and is also impacted by the removal of wood for charcoal production. Strip mining to remove basaltic rock (e.g. in CoaCoatzincla) is also a threat, resulting in the removal of forest. Furthermore, some populations have been damaged by poachers who collect plants to sell.
- Ceratozamia mexicana Brongn.
Ceratozamia mexicana Brongn.
Ann. Sci. Nat., Bot. sér. 3, 5: 8 (1846)
- Ceratozamia mexicana Brongn.
- Ceratozamia mexicana var. vulgaris J.Schust.
- Dipsacozamia mexicana (Brongn.) Liebm. ex Dyer in Hemsl.
- Zamia mexicana (Brongn.) Linden
- Ceratozamia mexicana var. tenuis Dyer
- Ceratozamia mexicana f. tenuis (Dyer) J.Schust.
- Ceratozamia purpurea Matte
- Macrozamia breviformis J.Schust.
- Zamia atropurpurea J.Parm. ex Miq.
- Zamia galeottii de Vriese
- Palmifolium galeottii (de Vriese) Kuntze
- Zamia macrophylla J.Parm. ex Miq.
ENGLISH: Horned cycad, Horned zamia
CZECH (Čeština): Ceratozamie mexická
UKRAINIAN (Українська): Цератозамія мексиканська
Description: Ceratozamia mexicana is a dioecious, medium-sized cycad with aerial or subterranean stems. On its top it carries a tuft consisting of 10 to 20 leaves, 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). Some variation can occur in leaflet width and length growth of this species that tend to be upright.
Distinguishing characters: Ceratozamia mexicana distinguish for its leaflets that are articulated and lacks an obvious midrib, they straight to subfalcate and coriaceous. 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, cylindrical or globose dark brown, erect, 10-50(-200) cm long, and then comparatively thin, bent or procumbent; bases of old leaves absent.
Leaves (fronds): (5-)10-20, pinnate, arching, 1-3 m long. Leaflets 14-150, simple, entire, articulated, inserted near the edges of the rachis towards the adaxial side, lacking a differently coloured basal gland, dark green, glossy, with numerous bifurcating parallel veins and no distinct midrib. Blades lanceolate to linear to falciform and coriaceous, around 250 mm in length, relatively narrow, 6-30 mm wide and usually concave, apices acute, lower leaflets not reduced to spines. Petioles with prickles. Leaves bright green to olive to dark green glossy, pubsecent, at least when young, with unbranched, transparent and coloured hairs. Stomata on lower surface only or on both surfaces.
Pollen Cones: Cylindrical to elliptic, 20-60 cm long, microsporophylls numerous, each with a pair of recurved horns.
Seed Cones: Cylindrical; 30-40 cm long; megasporophylls 200 or more, each with a pair of recurved horns.
Seeds: Yellow white.
Bibliography: Major references and further lectures
1) Vazquez, M., Bojorquez, H., Torres, L., Sanchez-Moreno, S., Sanchez-Morales, L. & Torres-Hernandez, L. 2010. Ceratozamia mexicana. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 15 January 2015.
2) Whitelock Loran M., "Classification Concepts in Ceratozamia (Zamiaceae)" in "Cycad classification: concepts and recommendations", CABI, 2004, p.109
3) Whitelock, Loran M., "The Cycads", Timber press, 2002
4) Haynes J.L, "World List of Cycads: A Historical Review", IUCN/SSC Cycad Specialist Group, 2011
5) Terrence Walters, Roy Osborne “Cycad Classification: Concepts and Recommendations” CABI, 12 gen 2004
6) Wikipedia contributors. "Ceratozamia mexicana." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 27 Feb. 2014. Web. 15 Jan. 201
7) V.P. Singh “Australia and Its Geography” Sarup & Sons, 2010
8) George E. Burrows, Ronald J. Tyrl “Toxic Plants of North America” John Wiley & Sons, 15 October 2012
9) Pál Greguss “Xylotomy of the Living Cycads: With a Description of Their Leaves and Epidermis” Akadémiai Kiado, 1968
10) Keith Boyer “Palms and Cycads Beyond the Tropics: A Guide to Growing Cold-hardy Species” Publication Fund, Palm & Cycad Societies of Australia, 1992
Cultivation and Propagation: Ceratozamia mexicanais a beautiful palm-or fern-like plant with long pinnate, arching fronds, with new growth emerging pinkish or coppery green. The only problem is that it is slow growing, however good growth conditions can speed it up considerably. It is also cultivated as an indoor plant in temperate countries.
Exposition: It prefers bright light exposure but colour bleaches when in full sun; best with some protection from afternoon heat but not in constant deep shade.
Soil: Needs a neutral, well drained sandy soil spot, with deep soil, but will still thrive in less than ideal conditions. Mulch with organic materials (bark or leaf mould).
Moisture: Water when dry. Drought tolerant.
Fertilization. Because of its growth habit, fertilize only when terminal bud begins to swell, indicating the start of the annual growth cycle.
Hardiness: It should be protected from extreme cold. (USDA Zones 9-11) Sustains leaf damage at -2° C.
Maintenance: Minimal; removal of offsets if desired, removal of spent fronds
Use: Landscape as cultivated perennial in warm areas, it makes a great accent or specimen plant. Several can be planted together for a lush, tropical effect. Plant on three to five-foot-centers to create a mass planting. Use near the patio, in mixed foundation plantings or in perennial beds. It is a spectacular house-plant or interior-scape specimen in cool areas tough enough to survive occasional neglect and harsh indoor environments.
Warning: Seeds of Ceratozamia mexicana are considered edible (Standley and Steyermark 1958) though they are poisonous unless cooked. However all parts of the plant are poisonous to animals and humans. The toxicity causes liver and kidney failure, as well as eventual paralysis. Dehydration sets in very quickly. No treatment for the poisoning is currently known. Poisonous Parts: Fleshy seeds, leaves. Protect pets and instruct children to never eat or chew any plant material without permission.
Propagation: Seeds. The germination process is very slow and difficult to achieve in cultivation, after fertile seeds are collected, they usually need several months of storage before the inner embryo is ready to germinate. Therefore, it is best to clean the seeds of external fruit and set them aside before attempting to propagate the seeds. Seeds should be sown in shallow container, lightly covered with sand, and after germination, potted off in small pots of moderately rich, light soil. The growing plants do best in partial shade. The old plants occasionally send up suckers around the base of the trunk. These may be taken off when in a dormant state and rooted, care being taken to remove the leaves to guard against excessive transpiration. The advantage of the "pups" is that you will know its sex, for seedlings you will have to wait several years until the plant flowers to find out.
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