The Zamiaceae are a family of

cycad 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 ...

s that are superficially palm or fern-like. They are divided into two subfamilies with eight genera and about 150 species in the tropical and subtropical regions of

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, Australia and

North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' is ...

and South America. The Zamiaceae, sometimes known as zamiads, are

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

, evergreen, and

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

. They have subterranean to tall and erect, usually unbranched, cylindrical stems, and stems clad with persistent leaf bases (in Australian genera). Their

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

are simply pinnate, spirally arranged, and interspersed with cataphylls. The leaflets are sometimes dichotomously divided. The leaflets occur with several sub-parallel, dichotomously branching longitudinal veins; they lack a mid rib. Stomata occur either on both surfaces or undersurface only. Their roots have small secondary roots. The coralloid roots develop at the base of the stem at or below the

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

surface. Male and female

sporophyll A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls (whether they are microphylls or megaphylls) bear either megasporangia and thus are called megasporophylls, or ...

s are spirally aggregated into determinate

cones A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines con ...

that grow along the axis. Female sporophylls are simple, appearing peltate, with a barren stipe and an expanded and thickened lamina with 2 (rarely 3 or more) sessile

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the fem ...

s inserted on the inner (axis facing) surface and directed inward. The seeds are angular, with the inner coat hardened and the outer coat fleshy. They are often brightly colored, with 2 cotyledons. One subfamily, the Encephalartoideae, is characterized by spirally arranged sporophylls (rather than spirally orthostichous), non-articulate leaflets and persistent leaf bases. It is represented in Australia, with two genera and 40 species. As with all cycads, members of the ''Zamiaceae'' are

poison Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...

ous, producing poisonous

glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...

s known as cycasins.

Genera

* Subfamily

Encephalartoideae The Zamiaceae are a family of cycads that are superficially palm or fern-like. They are divided into two subfamilies with eight genera and about 150 species in the tropical and subtropical regions of Africa, Australia and North and South Americ ...

** Tribe

Diooeae ''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. Description Dioons are dioecious, palmli ...

*** ''

Dioon ''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. Description Dioons are dioecious, p ...

'' (14 species) ** Tribe Encephalarteae *** Subtribe

Encephalartinae ''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 ge ...

**** ''

Encephalartos ''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 ge ...

'' (66 species) *** Subtribe Macrozamiinae **** ''

Macrozamia ''Macrozamia'' is a genus of around forty species of cycads, family Zamiaceae, all of which are endemic to Australia. Many parts of the plant have been utilised for food and material, most of which is toxic if not processed correctly. Descript ...

'' (42 species) **** ''

Lepidozamia ''Lepidozamia'' is a genus of two species of cycad, both endemic to Australia. They are native to rainforest climates in eastern Queensland and eastern New South Wales. They have a diploid chromosome number of 2n = 18. Etymology The name is deri ...

'' (2 species) * Subfamily Zamioideae ** Tribe Ceratozamieae *** '' Ceratozamia'' (27 species) ** Tribe Zamieae *** Subtribe Microcycadinae **** '' Microcycas'' (1 species) *** Subtribe Zamiinae **** '' Chigua'' (2 species) **** ''

Zamia ''Zamia'' is a genus of cycad of the family Zamiaceae, native to North America from the United States (in Georgia and Florida) throughout the West Indies, Central America, and South America as far south as Bolivia. The genus is considered to be ...

'' (76 species) * †Subfamily Eostangerioideae ** †'' Eostangeria'' (3 species) Some classifications also place the genus ''

Bowenia The genus ''Bowenia'' includes two living and two fossil species of cycads in the family Stangeriaceae, sometimes placed in their own family Boweniaceae. They are entirely restricted to Australia. The two living species occur in Queensland. '' ...

'' in Zamiaceae.

Gallery

File:Dioon edule03.jpg, ''

Dioon edule ''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.The United States Botanical Garden It belongs to the Zamiaceae plant ...

'' File:Dioon mejae.jpg, '' Dioon mejiae'' File:E.altensteinii kg 011.jpg, ''

Encephalartos altensteinii ''Encephalartos altensteinii'' is a palm-like cycad in the family Zamiaceae. It is endemic to South Africa. The species name ''altensteinii'' commemorates Altenstein, a 19th-century German chancellor and patron of science. It is commonly known a ...

'' File:Encephalartos lebomboensis - Lebombo cycad - desc-fruiting stalk.jpg, ''

Encephalartos lebomboensis ''Encephalartos lebomboensis'' is a species of cycad in the family Zamiaceae. Native to the Lebombo Mountains of South Africa, the species was first described in 1949 by the South African botanist Inez Verdoorn. It is commonly known as the Lebo ...

'' File:Lepidozamia peroffskyana at Kerikeri, Bay of Islands, New Zealand.jpg, ''

Lepidozamia peroffskyana ''Lepidozamia peroffskyana'' is a palm-like cycad in the family Zamiaceae. It is endemic to eastern Australia. The species is named after Count Peroffsky (1794-1857), benefactor of the St. Petersburg Botanical Garden. Description left, Le ...

'' File:Macrozemia moorei.jpg, ''

Macrozamia moorei ''Macrozamia moorei'' is a cycad in the family Zamiaceae, native to Queensland ( Australia). The species was described by Ferdinand von Mueller in 1881, naming it after Charles Moore (1820–1905), director of the Royal Botanic Gardens, Sydney ...

'' File:Ceratozamia Hildae Leave.jpg, '' Ceratozamia hildae'' File:Microcycas calocoma01.jpg, '' Microcycas calocoma'' File:Zamia furfuracea04.jpg , ''

Zamia furfuracea ''Zamia furfuracea'' is a cycad endemic to southeastern Veracruz state in eastern Mexico. Names Although not a palm tree (Arecaceae), its growth habit is superficially similar to a palm; therefore it is commonly known as cardboard palm or cardbo ...

References

The Cycad Pages: ZamiaceaeFlora of North America
* {{Taxonbar, from=Q133329 Cycads Plant families