Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or female. Cycads vary in size from having trunks only a few centimeters to several meters tall. They typically grow very slowly and live very long. Because of their superficial resemblance, they are sometimes mistaken for palms or ferns, but they are not closely related to either group.
The gymnosperms are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes, forming the clade Gymnospermae. The term gymnosperm comes from the composite word in Greek: γυμνόσπερμος, literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds. The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or on their own as in yew, Torreya, Ginkgo. Gymnosperm lifecycles involve alternation of generations. They have a dominant diploid sporophyte phase and a reduced haploid gametophyte phase which is dependent on the sporophytic phase. The term "gymnosperm" is often used in paleobotany to refer to all non-angiosperm seed plants. In that case, to specify the modern monophyletic group of gymnosperms, the term Acrogymnospermae is sometimes used.
Stangeria eriopus is a cycad endemic to southern Africa. It is the sole species in the genus Stangeria, most closely related to the Australian genus Bowenia, with which it forms the family Stangeriaceae.
Zamia is a genus of cycad of the family Zamiaceae, native to North America from the United States throughout the West Indies, Central America, and South America as far south as Bolivia. The genus is considered to be the most ecologically and morphologically diverse of the cycads, and is estimated to have originated about 68.3 million years ago.
Encephalartos is a genus of cycad native to Africa. Several species of Encephalartos are commonly referred to as bread trees, bread palms or kaffir bread, since a bread-like starchy food can be prepared from the centre of the stem. The genus name is derived from the Greek words en (within), kephalē (head), and artos (bread), referring to the use of the pith to make food. They are, in evolutionary terms, some of the most primitive living gymnosperms.
Dioon is a genus of cycads in the family Zamiaceae. It is native to Mexico and Central America. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes.
Dioon edule, the chestnut dioon, is a cycad native to Mexico, also known as palma de la virgen. Cycads are among the oldest seed plants and even pre-date the dinosaurs. It belongs to the Zamiaceae plant family within the order Cycadales. The genus name "Dioon" means "two-egged", referring to the two ovules.
Ceratozamia is a genus of New World cycads in the family Zamiaceae. The genus contains 27 known currently living species and one or two fossil species. Most species are endemic to mountainous areas of Mexico, while few species extend into the mountains of Guatemala, Honduras and Belize. The genus name comes from the Greek ceras, meaning horn, which refers to the paired, spreading horny projections on the male and female sporophylls of all species.
Microcycas is a genus of cycads in the family Zamiaceae containing only one species, Microcycas calocoma, endemic to a small area in western Cuba in Pinar del Río Province. It is estimated that there are 50-249 mature individuals left in the wild.
Chigua is a genus of cycads in the family Zamiaceae containing two species, endemic to small areas in northwestern Colombia. Described by botanist Dennis Stevenson in 1990, it is the most recently named genus, and the name refers to a Spanish transliteration of the common name given to cycads by the indigenous peoples of Colombia. The species are found in wet lowland rainforests at 100–200 m altitude.
Macrozamia dyeri, known as djeeri, is a species of plant in the family Zamiaceae. It is endemic to Western Australia, occurring near Esperance. The seeds are consumable when prepared correctly and were an important resource to people of the region, but the plant is otherwise toxic to many species.
Macrozamia glaucophylla is a species of cycad from the genus Macrozamia and the family Zamiaceae. Endemic to New South Wales, Australia, this species has features that resembles palms, although both species are taxonomically quite different. The current population trend of Macrozamia glaucophylla is stable with 2,500 to 10,000 mature individuals. The species are found in several habitats including forest and savanna. Ecologically, Macrozamia glaucophylla lives in terrestrial system, a land-based community of organisms where the biotic and abiotic components interact in the given area.
Macrozamia heteromera is a species of cycad in the family Zamiaceae initially discovered by Charles Moore in 1858 and is endemic to New South Wales, Australia. It can be found in the north-western region of New South Wales within the Warrumbungle mountains and further south west towards the Coonabarabran district. It is a low trunked cycad usually at a height below 1 metre and can be found in dry sclerophyll woodlands. M. heteromera can be distinguished from the rest of the Macrozamia genus by its mid-green, narrow, usually divided pinnae and divided seedling pinnae. It is a plant that has toxic seeds and leaves, a characteristic common to cycads. However, after proper preparation and procedure, the seeds are fine for consumption.
Macrozamia miquelii, is a species of cycad in the plant family Zamiaceae. It is endemic to Queensland and New South Wales in Eastern Australia. Located within sclerophyll forests dominated by eucalyptus trees, the cycad grows on nutrient-poor soils. It is recognised within the Zamiaceae family for its, medium height at 1 m, intermediate size of male and female cones and lighter green leaves compared to other cycads within the plant family of Zamiaceae. The seeds have an orange red sarcotesta which attracts fauna consumption, allowing a mutualistic seed dispersal for the cycad. These seeds are also edible for human consumption if prepared correctly to remove the toxins.
Macrozamia mountperriensis is a species of plant in the family Zamiaceae endemic to the area around Mount Perry in Queensland; however, it is not considered threatened due to its large population in the area. The species was discovered by colonial botanists including Frederick Manson Bailey and James Keys in the late 1800s. All members of the Zamiaceae family are considered to be poisonous.
Macrozamia spiralis is a species of cycad in the family Zamiaceae. It is endemic to New South Wales in eastern Australia, where it is found in sclerophyll forest on low-nutrient soils. Plants generally lack a trunk and have 2–12 leaves that range up to 100 cm (40 in) in length.
Oxycorynini are a tribe of American belids, primitive weevils of the family Belidae. Like in other belids, their antennae are straight, not elbowed as in the true weevils (Curculionidae). In contrast to other Belidae, Oxycorynini larvae feed on flowers or several types of fruit.
Aulacaspis yasumatsui, or cycad aulacaspis scale (CAS), is a scale insect species in the genus Aulacaspis that feeds on cycad species such as Cycas revoluta or Dioon purpusii. Other common names include the cycad scale, the sago palm scale, and the Asian cycad scale. This is a serious pest of cycads which can kill its host plant.
Zamia integrifolia, also known as coontie palm, is a small, tough, woody cycad native to the southeastern United States, the Bahamas, Cuba, and the Cayman Islands.
