The Casuarinaceae are a family of dicotyledonous flowering plants placed in the order Fagales, consisting of four

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

and 91 species of trees and shrubs native to eastern Africa,

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, Southeast Asia, Malesia, Papuasia, and the

Pacific Islands Collectively called the Pacific Islands, the islands in the Pacific Ocean are further categorized into three major island groups: Melanesia, Micronesia, and Polynesia. Depending on the context, the term ''Pacific Islands'' may refer to one of se ...

. At one time, all species were placed in the genus '' Casuarina''. Lawrence Alexander Sidney Johnson separated out many of those species and renamed them into the new genera of '' Gymnostoma'' in 1980 and 1982, '' Allocasuarina'' in 1982, and '' Ceuthostoma'' in 1988, with some additional formal descriptions of new species in each other genus. At the time, it was somewhat controversial. The monophyly of these genera was later supported in a 2003 genetics study of the family. In the Wettstein system, this family was the only one placed in the order Verticillatae. Likewise, in the Engler, Cronquist, and Kubitzki systems, the Casuarinaceae were the only family placed in the order Casuarinales. Members of this family are characterized by drooping equisetoid (meaning "looking like '' Equisetum''"; that is, horsetail) twigs, evergreen foliage,

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is conne ...

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 ...

and infructescences ('fruiting bodies') cone-like, meaning combining many outward-pointing valves, each containing a seed, into roughly spherical, cone-like, woody structures. The roots have nitrogen-fixing nodules that contain the soil actinomycete '' Frankia''. In Australia the most widely used common name for Casuarinaceae species is sheoak or she-oak (a comparison of the timber quality with English oak). Other common names in Australia include ironwood, bull-oak or buloke, beefwood, Cox states that the name 'she-oak' is derived from Native America ''sheac'' — beefwood. or cassowary tree. The Shire of Buloke in Victoria, Australia, is named after the species '' Allocasuarina luehmannii''.

Systematics

Modern molecular phylogenetics suggest the following relationships:

References

External links

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Research team
fro
IRD
working on '' Frankia''-Casuarinaceae mycorrhizal and nitrogen-fixing

symbioses Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

* * {{Taxonbar, from=Q474620 Rosid families Taxa named by Robert Brown (botanist, born 1773)