Cycadales are a lineage of gymnosperms (Gymnospermae), plants that produce pollen and seeds in cones or strobili. These plants are distributed mainly in tropics and subtropics of the world. The Cycadales order is composed by the families Cycadaceae, with the genus Cycas (120 species); and Zamiaceae composed by the genera, Bowenia (2), Ceratozamia (35), Dioon (18), Encephalartos (65), Lepidozamia (2), Macrozamia (41), Microcycas (1), Stangeria (1), and Zamia (83).
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Among seed plants (Gymnosperms and Angiosperms) Cycads are a very ancient lineage. Cycads appear in the fossil record in the Permian, towards the end of the Paleozoic era (more than 200 millions of years ago). During the Mesozoic era, Cycads were dominant plants in the ecosystems (at the same time with Dinosaurs). Most of the Mesozoic seed plants lineages are extinct, but Cycads have remained in tropical ecosystems until our time. In addition to being living fossils, Cycads have many unique characters that make them very interesting among seed plants. Therefore, Cycads represent an invaluable lineage of plants that warrants important conservation efforts.
Currently there are 366 known Cycad species in the world until 2021 belonging to 10 genera and 2 families, however, this number is changing constantly. Cycads exhibit great species richness in countries like Australia (85 spp), Mexico (66 spp), South Africa (40 spp), China (27 spp), Colombia (26 spp) and Panama (17 spp). These species of Cycads include arborescent, herbaceous and even epiphytes forms. Cycads occur from deserts and savannas, to mountains and tropical forest ecosystems worldwide.
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In countries like Australia, South Africa, China, Mexico and USA, Cycads are plants widely recognized as a very important ornamental group of plants in the horticultural market. In another regions Cycads have traditional uses by the human communities, who used them as food, medicine, magic – religious, among others. Unfortunately, these traditional uses and the horticulture interest for Cycads have generated an illegal trade of many species, in some cases this trade has resulted in serious threats for wild populations in some countries.
The IUCN Red list for threatened species has evaluated several groups of organisms at the global level. According to these evaluations, Cycads are one of the most threatened organisms in the world, with more than 60% of their species listed as in risk of extinction. The main threat for Cycad species is habitat destruction and degradation, and in some cases overexploitation of populations for trade. Because of this, Cycads have become a very charismatic group of plants for biodiversity conservation globally.
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To know more information about every genus of Cycadales of the world, click the picture of the corresponding genera in the next infographic:
Endemic to the Neotropics in Mesoamerica, it is composed of 18 species. It is distributed in Mexico and Honduras on rock formations and cliffs, dry forests almost deserted, to tropical rainforests, from sea level to 2100 meters. Dioon comes from the Greek roots "di" (two) and "ōon" (egg), referring to the typical two seeds contained in megasporophylls. They are small and medium-sized plants, up to large individuals with stems of 16 meters, composed of up to 50 dull whitish green to shiny dark green leaves, up to 2 meters long. Megastrobili are ovoid and large, covered by a dense layer of grayish tomentum; microstrobili are elliptic to ovoid, light to grayish, covered or not by velvety indumentum. It is a genus very appreciated by collectors and gardeners which has been the object of extraction of wild populations, it has also been affected by the loss of its habitat due to the expansion of the agricultural frontier. Currently, some species are frequently cultivated in front gardens or open spaces in Mexico and the United States. Researchers at the Montgomery Botanical Center have documented the largest and heaviest female cone of this genus which reached almost 1 meter in length and weighed 65 kg, 34 of which corresponded to the seeds. Dioon has 6 Endangered (EN), 5 Vulnerable (VU), 2 Near Threatened or Least Concern (NT/LC) and 5 not assessed species. All Dioon species are listed in Appendix II of Cites.
Endemic to the Neotropics in Mesoamerica, it is composed of 37 species. It is distributed in Mexico, Belize, and Guatemala, on tropical rainforest, cloud forest, dry forest of pine and oak and deserts, from sea level to 1800 meters. From the Greek root "keratos" (horn) and Zamia (Cycadales genus), referring to plants with two horn-shaped projections present in the megastrobili and microstrobili. They are plants with rhizomes from subterranean to subarborescent, reaching up to 3 meters, composed of 30 leaves up to 3.6 meters, dark green to coppery, glabrous or covered by indumentum, which exhibit a great variety in both shapes and sizes. Megastrobili are grayish to olive green; microstrobili are beige to light green, both with conspicuous projections on the surface of the sporophylls. It is a genus very appreciated in the ornamental industry due to its morphological variety and its ability to establish in diverse habitats. Many species have been severely affected by the extraction of individuals from wild populations. Ceratozamia has 6 Critically Endangered (CR), 12 Endangered (EN), 2 Vulnerable to Extinction (VU), 1 Near Threatened (NT) and 16 not assessed species. All Ceratozamia species are listed in Appendix II of Cites.
Endemic and monotypic of the Neotropics in the Antilles of the Caribbean Sea. It is endemic to Cuba and grows in shady or open habitats, inside forests and dry grasslands from 50 to 250 meters. Is composed by the species Microcycas calocoma. The name of the genus comes from the Greek root "micro" (small) and Cycas (Cycadales genus); the epithet comes from the Latin root "calocoma" and means “beautiful crown of leaves”. They are arborescent plants with stems up to 10 meters, with 50 shiny dark green leaves up to 1.2 meters. Megastrobili are cylindrical, light brown to dark yellow, with 2 round protuberances on the sporophylls; microstrobili are cylindrical, light brown to dark yellow, with short peduncle. It is a highly appreciated genus in the ornamental industry due to its rarity and its resistance to establishing itself in open places with full exposure. Microcycas is endangered by the habitat loss due to deforestation and expansion of the agricultural frontier. The only species of this genus is Critically Endangered (CR) and is listed in Appendix I of Cites.
Endemic to the Neotropics in Mesoamerica and South America, it is composed of 83 species, distributed in: United States, Mexico, Costa Rica, Panama, Colombia, Venezuela, Brazil, Ecuador, Bolivia and Peru, in habitats such as tropical rainforests above sea level, through dry forests and rocky cliffs, to low montane tropical rainforests up to 2200 meters. Zamia comes from the new Latin, apparently from a derivation or misinterpretation of the Latin expression "azania", which is a kind of pine cone. They are small and medium-sized plants, up to large individuals with stems of 10 meters, composed of up to 40 leaves of a wide variety of colors in prefoliation that include among others: white, red, pink, orange, copper, light green and dark green and can measure up to 3.5 meters. Megastrobili are cylindrical, brown or red wine, covered by indumentum, with long peduncles; microsrobili are elliptic, small to tiny, light to brown, covered by velvety indumentum. It is a very important genus in the ornamental industry, sought after by collectors and gardeners, which has been subject to extraction from its natural habitat, as well as the loss of its habitat due to the expansion of the agricultural frontier, cattle ranching and deforestation. Many species of Zamia are used by different communities in the Americas as food, medicinal or magical-religious, also, some species are commonly cultivated in front gardens or open spaces in: United States, Mexico, Costa Rica, Panama, Colombia and Brazil. Among the cultivated species the best known is Z. furfurácea native to Mexico, which paradoxically, is threatened in the wild. Colombia has the largest number of species in the world with 26 described species, 18 of which are endemic. Zamia has 21 Critically Endangered (CR), 16 Endangered (EN), 11 Vulnerable to Extinction (VU) and 35 Near Threatened, Least Concern or Data Deficient (NT/LC/DD) species. All species are listed in Appendix II of CITES.
Endemic to the tropics and subtropics of the old world in Africa, it is composed of 65 species, distributed from central Africa to northern South Africa, in countries such as Sudan, Nigeria, South Africa, Congo, Uganda, Zimbabwe and Mozambique, in desert habitats, savannahs and forests, from sea level to over 2000 meters, with some species that can tolerate snowfall. From the Greek roots "en-" (inside), "cephale" (head) and "artos" (bread), it refers to the starch extracted from the stems for the elaboration of food by African communities. They are plants with a great morphological variety, from medium-sized with subterranean rhizomes to arborescent with stems up to 15 meters, with gray, yellow-green or dark green leaves from 60 cm to 6 meters. Megastrobili and microstrobili may be blue-gray, light green, brown, yellow, orange, pink or red. Encephalartos is commonly known as "bread palm", since some communities extract starch from the stems to prepare this food. It is a genus highly sought after by collectors and gardeners and is commonly cultivated in front gardens in South Africa. Unfortunately, it has 4 species extinct in the wild (EX), 17 Critically Endangered (CR), 10 Endangered (EN), 15 Vulnerable (VU) and 19 Near Threatened or Least Concern (LC/NT). All species are listed in Appendix I of CITES.
A genus widely distributed in the tropics and subtropics of the old world in Southeast Asia and Africa. It is composed of 120 species, distributed from the east coast of Africa in Madagascar, through Southeast Asia to northern Australia, in countries such as Madagascar, India, Philippines, Japan, China, Taiwan, Thailand, Indonesia and Australia. It is a genus of wide distribution in temperate and tropical, humid and dry sites, in habitats such as: deserts, savannas, tropical rainforests, rock formations, from sea level to over 2000 meters. Cycas comes from the Greek word "kykas" (palm), and it refers to the resemblance of these plants to palms (Arecaceae). They can be small and medium-sized plants with subterranean rhizomes, to arborescent with branched stems and up to 12 meters. The leaves can measure from 50 cm to 4 meters, they have circinate prefoliation similar to that of pteridophytes (unique character in Cycadales order) and lustrous laminae without indumentum or covered with light trichomes; leaflets have a median vein, and are of grayish to dark green coloration. Megastrobili are laminar, spatulate, on the margins of which the seeds are arranged; microstrobili are cylindrical to ovoid, brown or beige, quite aromatic. Many species have been used as food by extracting starch from stems and seeds, however, in communities where their use has been reported, some diseases have also been reported as a result of inadequate preparation of these parts which contain abundant toxins. It is a genus much sought after by collectors and gardeners, commonly cultivated in front gardens around the world, mainly the species C. revoluta, C rumphii and C. thouarsii. It has 11 Critically Endangered (CR), 15 Endangered (EN), 29 Vulnerable (VU) and 41 Near Threatened, Least Concern or Data Deficient (NT/LC/DD) and 22 not assessed species. All species are listed in Appendix II of CITES.
Endemic and monotypic of the old world tropics in South Africa, is composed with the species Stangeria eriopus. Its distribution is restricted to a small area in South Africa, and grows in open sites, grasslands or within moist eucalyptus forests, from sea level to 750 meters. It is named in honor of the topographer William Stanger. They are small plants with subterranean rhizomes that branch producing multiple heads with up to 3 leaves of up to 2 meters per head, green to copper-colored, covered by a delicate white indumentum. Megastrobili are brown or gray, cylindrical, covered by soft indumentum; microstrobili are light brown. Resembling a fern, in fact, the first description of the species was considered part of the pteridophyte genus Lomaria. The plants are extracted from the wild and are widely used as medicinal plants, being traded in traditional markets in Southafrica. It is much sought after by collectors and gardeners because of its pteridophyte-like appearance, but with strobili typical of a gymnosperm. S. eropus is Vulnerable (VU) and is listed in Appendix I of Cites.
Endemic to the old world in Australia, it is composed of 41 species, distributed in a wide variety of habitats such as humid forests near the coast or inland, and even in deserts, from sea level to 1500 meters. From the Greek root "macros" (large) and Zamia (Cycadales genus), referring to large, usually arborescent, Zamia-like plants. They are from small plants, with subterranean rhizomes, to arborescent plants with stems of up to 8 meters, with 150 dark green to blue-gray leaves, which can reach up to 3 meters. Megastrobili and microstrobili ranging in coloration from dark green to almost white, with sporophylls in some species with a very prominent rigid spine. Australian communities extract starch from stems and seeds effectively eliminating toxins, however, cattle have been reported to be poisoned by ingesting some parts of these plants. This genus is very sought after in the ornamental industry due to its diversity of species, the diversity of habitats where it can establish and the hardiness of some species to establish in open sites. Its species have been subjected to extraction pressures from the natural environment, affecting some populations. Macrozamia has 8 Endangered (EN), 9 Vulnerable (VU) and 24 Near Threatened or Least Concern (NT/LC) species. All species are listed in Appendix II of Cites.
Endemic to the old world in the Queensland coast in Australia, it is composed of 2 species restricted to the northeast coast of Australia, where it occurs in habitats such as wet forests above sea level up to 600 meters. It is named in honor of Sir George Ferguson Bowen, first governor of Queensland. They are plants with subterranean rhizomes, composed with dark green bipinnate leaves and lustrous laminae up to 2 meters. Megastrobili are dark green; microstrobili are light green. Bowenia is highly sought after in the ornamental industry because of its remarkable compound leaves, which are very attractive to collectors and specialist gardeners. Both species of Bowenia are of Least Concern (LC) and are listed in Appendix II of Cites.
Endemic to the old world in the coasts of Queensland and South Wales in Australia, it is composed of 2 species, distributed in humid forests of the southern coast in Australia from sea level up to 650 meters. From the Greek root "lepidos" (scale) and Zamia (Cycadales genus), it refers to plants with scales covering the base of the leaves and stems. They are plants with arborescent stems that can reach up to 17 meters, with up to 150 dark green leaves, up to 3 meters. Megastrobili are striking for their size and the ornamentation of the megasporophylls; microstrobili are solitary and grayish in color. This genus is very sought after in the ornamental industry due to its hardiness to establish in open places or with few nutrients, its rapid growth, its inert petioles and its elegant reproductive structures. L. hopei is considered the species of the order Cycadales with the tallest stems reaching up to 17.5 meters. Both species are of Least Concern (LC) and are listed in Appendix II of Cites.
To know more about the species of the Cycadales of the world you can consult the next links of Cycads specialized pages:
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The World List of Cycads, online edition ... www.cycadlist.org |
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The World List of Cycads, online edition: https://www.cycadlist.org/ |
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IUCN / SSC Cycad Specialist Group IUCN/SSC Cycad Specialist Group\'s website www.cycadgroup.org |
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IUCN / SSC Cycad Specialist Group: http://www.cycadgroup.org/ |
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This is the facebook page for the online edition of The World List of Cycads (http://cycadlist.org),... web.facebook.com |
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The World List of Cycads: https://web.facebook.com/groups/808846832502133 |
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Welcome to the PACSOA website and wiki, one of the internet's most comprehensive resources about palms and cycads. This web site includes extensive information on palm... www.pacsoa.org.au |
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Pacsoa: http://www.pacsoa.org.au/wiki/Main_Page |
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SCC - Sociedad Colombiana de Cycadas - ONG
Medellín - Colombia
