The Casuarinaceae are a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

dicot The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, t ...

yledonous

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

s placed in the order Fagales, consisting of four genera and 91 species of trees and shrubs native to eastern

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,

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

, 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 ...

. 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 system The Kubitzki system is a system of plant taxonomy devised by Klaus Kubitzki, and is the product of an ongoing survey of vascular plants, entitled ''The Families and Genera of Vascular Plants'', and extending to 15 volumes in 2018. The survey, in ...

s, 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 In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

foliage, monoecious or

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 reproducti ...

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 ''Frankia'' is a genus of nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants, similar to the '' Rhizobium'' bacteria found in the root nodules of legumes in the family Fabaceae. ''Frankia'' also initiate the forming of ro ...

''. 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 Victoria is a state in southeastern Australia. It is the second-smallest state with a land area of , the second most populated state (after New South Wales) with a population of over 6.5 million, and the most densely populated state in ...

, is named after the species '' Allocasuarina luehmannii''.

Systematics

Modern

molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

suggest the following relationships:

References

External links

* *
Research team
fro
IRD
working on ''

''-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)