''Allocasuarina rigida'' is a species of flowering plant in the family

Casuarinaceae The Casuarinaceae are a family of dicotyledonous flowering plants placed in the order Fagales, consisting of four genera and 91 species of trees and shrubs native to eastern Africa, Australia, Southeast Asia, Malesia, Papuasia, and the Pacific ...

and is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to eastern Australia. It is a

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

shrub that has branchlets up to long, the leaves reduced to scales in whorls of seven to ten, and the fruiting cones long containing winged seeds long.

Description

''Allocasuarina rigida'' is dioecious shrub that typically grows to a height of and has smooth bark. Its branchlets are more or less erect and up to long, the leaves reduced to scale-like teeth long, arranged in whorls of seven to ten around the branchlets. The sections of branchlet between the leaf whorls are long, wide. Male flowers are arranged in spikes long, with about 4 to 6.5 whorls per centimetre (per 0.39 in.), and often appear like a string of beads, the

anthers The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filamen ...

long. Female cones are on a peduncle long, and mature cones are cylindrical to ovoid, long and in diameter, containing brown, winged seeds long.

Taxonomy

This sheoak was first formally described in 1848 by

Friedrich Anton Wilhelm Miquel Friedrich Anton Wilhelm Miquel (24 October 1811 – 23 January 1871) was a Dutch botanist whose main focus of study was on the flora of the Dutch East Indies. Early life Miquel was born in Neuenhaus and studied medicine at the University of Gr ...

who gave it the name ''Casuarina rigida'' in the journal, ''Revisio critica Casuarinarum'' from specimens collected near

Moreton Bay Moreton Bay is a bay located on the eastern coast of Australia from central Brisbane, Queensland. It is one of Queensland's most important coastal resources. The waters of Moreton Bay are a popular destination for recreational anglers and are ...

. In 1982, Lawrie Johnson transferred the species to ''Allocasuarina'' as ''A. rigida'' in the ''

Journal of the Adelaide Botanic Gardens The Adelaide Botanic Garden is a public garden at the north-east corner of the Adelaide city centre, in the Adelaide Park Lands. It encompasses a fenced garden on North Terrace (between Lot Fourteen, the site of the old Royal Adelaide Hospita ...

''. In the same journal, Johnson described two subspecies of ''A. rigida'' and the names are accepted by the

Australian Plant Census The Australian Plant Census (APC) provides an online interface to currently accepted, published, scientific names of the vascular flora of Australia, as one of the output interfaces of the national government Integrated Biodiversity Information Sys ...

: * ''Allocasuarina rigida'' subsp. ''exsul'' L.A.S.Johnson has branchlet sections long and mature cones long and wide * ''Allocasuarina rigida'' subsp. ''rigida'' L.A.S.Johnson has branchlet sections long and mature cones long and wide

Distribution and habitat

''Allocasuarina rigida'' grows in sandy soil on volcanic outcrops in exposed situations from the

McPherson Range The McPherson Range is an extensive mountain range, a spur of the Great Dividing Range, heading in an easterly direction from near Wallangarra, Queensland, Wallangarra to the Pacific Ocean coastline. It forms part of the Scenic Rim on the border ...

in south-eastern Queensland to the

Gibraltar Range National Park Gibraltar Range is a national park located in northeastern New South Wales, Australia. It is situated 79 kilometres (49 mi) northeast of Glen Innes and north of Sydney. The Park is part of the Washpool and Gibraltar Range area, which is ...

and Ebor in north-eastern New South Wales and in disjunct populations on Mount Cooroora in south-eastern Queensland and Big Nellie Mountain near

Taree Taree () is a city on the Mid North Coast, New South Wales, Australia. It and nearby Cundletown were settled in 1831 by William Wynter. Since then it has grown to a population of 26,381, and commands a significant agricultural district. Situ ...

in north eastern New South Wales. Subspecies ''exsul'' only occurs on Mount Cooroora and subsp. ''rigida'' occurs throughout the remainder of the range.

References

External links

Occurrence data for ''Allocasuarina rigida''
from The Australasian Virtual Herbarium {{Taxonbar, from1=Q15376673, from2=Q66103134, from3=Q95488667 rigida Fagales of Australia Flora of New South Wales Flora of Queensland Dioecious plants Taxa named by Friedrich Anton Wilhelm Miquel Plants described in 1848