Allocasuarina, commonly known as sheoak[4] or she-oak,[5] is a genus of flowering plants in the family Casuarinaceae and is endemic to Australia. Plants in the genus Allocasuarina are trees or shrubs with soft, pendulous, green branchlets, the leaves reduced to scale-like teeth. Allocasuarinas are either monoecious or dioecious, the flowers never bisexual. Male and female flowers are arranged in spikes, the female spikes developing into cone-like structures enclosing winged seeds.
The genera Allocasuarina and Casuarina are similar, and many formerly in the latter now included in Allocasuarina.
Description
Plants in the genus Allocasuarina are trees or shrubs with soft, pendulous, green branchlets, the leaves reduced to 4 to 14 scale-like teeth arranged around in whorls around ribbed, jointed branchlets. Allocasuarinas have separate male and female flowers, sometimes on one plant (monoecious), otherwise on separate male and female plants, (dioecious). Male flowers are arranged in spikes along branchlets that are usually different from the vegetative branchlets. Female flowers are in spikes on short side-branches, the female spikes later developing into cone-like structures enclosing winged seeds known as samaras.[3][4][5][6][7][8][9]
The genera Allocasuarina and Casuarina are similar, many formerly in the latter now included in Allocasuarina. There are 6 to 20 scale-like teeth in each whorl of casuarina leaves and the samaras are grey or yellowish-brown, the bracteoles of the fruiting cones thin, woody and extend well beyond the cone body. There are 4 to 14 scale-like teeth in each whorl of Allocasuarina leaves and the samaras are reddish-brown to black, the bracteoles thickly woody and extend only slightly beyond the cone body.[9]
Taxonomy
The genus Allocasuarina was first formally described in 1982 by Lawrence Johnson in the Journal of the Adelaide Botanic Gardens.[2] In the same paper, Johnson transferred some species previously included in Casuarina to the new genus, and nominated Allocasuarina torulosaAiton L.A.S.Johnson as the type species.[3] The name Allocasuarina means "other Casuarina".[10] ("Allo-" in Greek means "other".)[11]
Plants in the genus Allocasuarina usually grow in nutrient-deficient soils and are endemic to southern Australia, but 4 species occur in north-eastern Queensland, and one in the north of Western Australia.[7]
References
^"Allocasuarina". Australian Plant Census. Retrieved 21 April 2023.
^ ab"Allocasuarina"(PDF). Wildflower Society of Western Australia (Inc.), Perth Branch. Retrieved 21 April 2023.
^Entwisle, Timothy J.; Stajsic, Val. "Allocasuarina". Royal Botanic Gardens Victoria. Retrieved 21 April 2023.
^ abWilson, Karen L.; Johnson, Lawrence A.S. George, Alex S. (ed.). "Allocasuarina". Australian Biological Resources Study, Department of Climate Change, the Environment and Water: Canberra. Retrieved 21 April 2023.
^"Allocasuarina". State Herbarium of South Australia. Retrieved 21 April 2023.
^ abWilson, Karen L.; Johnson, Lawrence A.S. Wilson, Karen L. (ed.). "Family Casuarinaceae". Royal Botanic Garden Sydney. Retrieved 21 April 2023.
^Sharr, Francis Aubi; George, Alex (2019). Western Australian Plant Names and Their Meanings (3rd ed.). Kardinya, WA: Four Gables Press. p. 286. ISBN9780958034180.
^William T. Stearn (1992). Botanical Latin. History, grammar, syntax, terminology and vocabulary (4th ed.). Portland, Oregon: Timber Press. p. 367.
^"Allocasuarina". Plants of the World Online. Retrieved 21 April 2023.
^"Allocasuarina". Australian Plant Census. Retrieved 21 April 2023.
External links
Wikimedia Commons has media related to Allocasuarina.
