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, with some specimens known to be as much as 1,000 years old. Because of their superficial resemblance, they are sometimes mistaken for palms or ferns, but they are not closely related to either group.
Cycas pruinosa is a small to medium species of cycad, a palm-like seed plant. It is a widespread but sporadic species in the eastern and southern Kimberley region of Western Australia, occurring also in the Spirit Hills on Bullo River Station in the Northern Territory.
Cycas is a genus of plants belonging to a very ancient lineage, the Cycadophyta, which are not closely related to palms, ferns, trees or any other modern group of plants. They are evergreen perennials which achieved their maximum diversity in the Jurassic and Cretaceous periods, when they were distributed almost worldwide. At the end of the Cretaceous, when the non-avian dinosaurs became extinct, so did most of the cycas in the Northern Hemisphere.
Cycas revoluta, is a species of gymnosperm in the family Cycadaceae, native to southern Japan including the Ryukyu Islands. It is one of several species used for the production of sago, as well as an ornamental plant. The sago cycad can be distinguished by a thick coat of fibers on its trunk. The sago cycad is sometimes mistakenly thought to be a palm, although the only similarity between the two is that they look similar and both produce seeds. The leaves grow from the trunk and start out as small leaves near the centre of the plant.
Cycas balansae is a species of cycad in the genus Cycas, native to southwestern China and adjacent northern Vietnam, where it occurs in dense mountain rainforests.
Cycas beddomei is a species of cycad in the genus Cycas, native to India, where it is confined to a small area of Andhra Pradesh state in the Tirumala Hills in scrubland and brush covered hills.
Cycas cairnsiana is a species of cycad in the genus Cycas, native to northern Australia in northern Queensland on the Newcastle Range.
Cycas chamaoensis is named after the only known habitat of this species, on and near Khao Chamao mountain in Khao Chamao District, Thailand. Stems are arborescent, either erect or decumbent. Leaves numerous, exceeding 60 per crown, 1.2-2.5 meters in length, ending in terminal spine. Petiole 30–60 cm, glabrous and partially spiny. Leaflets in 85-155 pairs, and lanceolate, glabrous and angled forward at 60-70 degrees.
Balaka seemannii is a species of flowering plant in the family Arecaceae that is endemic to Fiji; growing in mixed forests on Vanua Levu and Taveuni islands.
Cycas micronesica is a type of cycad found in the island of Yap in Micronesia, the Marianas islands of Guam and Rota, and The Republic of Palau. It is commonly known as Federico nut or Fadang in Chamorro. The species, previously lumped with Cycas rumphii or Cycas circinalis, was described in 1994 by Ken Hill. Paleoecological studies have determined that C. micronesica has been present on the island of Guam for about 9,000 years. It is linked with the human degenerative disease Lytico-Bodig disease, which is similar to amyotrophic lateral sclerosis (ALS) through a neurotoxin (BMAA) in the seeds, which were a traditional food source on Guam until the 1960s.
Cycas taitungensis is a species of genus Cycas endemic to Taitung County, south-eastern Taiwan. C. taitungensis, an evergreen tree, can grow up to about 5 m (16 ft) tall. The species was not described until 1994, but its specimen was once applied as the type of species Cycas taiwaniana, which is not really distributed in Taiwan according to the further research.
Cycas pectinata was the fourth species of Cycas to be named; it was described in 1826 by Scottish surgeon and botanist Francis Buchanan-Hamilton from Kamrup, Assam in northeast India. The species is one of the most widespread cycads. It is found in the northeastern part of India, Nepal, Bhutan, northern Burma, southern China (Yunnan), Bangladesh, Burma, Malaysia, Cambodia, northern Thailand, Laos, and Vietnam. Cycas pectinata usually grow at elevation 300 m to 1200 m and in difficult terrains. In China, it grows in dry, open thickets in limestone mountains, red soil in sparse monsoon forests. Cycas pectinata grows up to 40 feet (12 m) tall and has very large, ovoid male cones. The tallest Cycas pectinata is a female plant in North Kamrup, Assam which measures 52.8 feet (16.1 m). The tree is the world's tallest Cycas plant. In Northeast India, the species is under severe threat due to clearing of forest and over collection of male cones for preparation of traditional medicines. The species is listed in CITES Appendix II and IUCN Redlist.
Cycas rumphii, commonly known as queen sago or the queen sago palm, is a dioecious gymnosperm, a species of cycad in the genus Cycas native to Indonesia, New Guinea and Christmas Island. Although palm-like in appearance, it is not a palm.
Cycas thouarsii, the Madagascar cycad, is an evergreen arborescent cycad in the genus Cycas. It is named after a French botanist Louis-Marie Aubert du Petit-Thouars (1758—1831).
Cycas ferruginea is a plant species native to Vietnam and to the Guangxi region of China. It grows on rocky crevices in forested areas at elevations of 200–500 m. It is known from a belt of limestone bluffs in Lang Son Province and Thai Nguyen Province in Vietnam, and in western Guangxi Province, China. It is also cultivated at the Guilin Botanical Garden, Guangxi.
Cycas clivicola is a species of cycad in Thailand, Cambodia, Vietnam, and Malaysia. It is found on limestone outcrops, as well as on offshore islands.
Cycas diannanensis is a species of cycad endemic to Yunnan, China.
Cycas fugax is a species of cycad endemic to Vietnam. It has only been recorded in the wild from Phu Tho Province, Vietnam, but may be reasonably common in cultivation in Hanoi.
Cycas wadei is a species of cycad endemic to Culion island, Philippines. There is only one subpopulation of about 5,000 mature individuals, located in a small area to the east of Halsey Harbor.
Cycas shanyaensis is a species of cycad endemic to Hainan, China.
