Allocasuarina duncanii

Allocasuarina duncanii, commonly known as Duncan's sheoak, or conical sheoak, is a species of flowering plant in the family Casuarinaceae and is endemic to Tasmania. It is a small dioecious tree that has branchlets up to long, the leaves reduced to scales in whorls of seven to nine, and the fruiting cones long containing winged seeds long.

Description

Allocasuarina duncanii is a small, erect, dioecious tree that typically grows to a height of up to. Its branchlets are up to long, the leaves reduced to scale-like teeth long, arranged in whorls of seven to nine around the branchlets. The sections of branchlet between the leaf whorls are long and wide. Male flowers are arranged in head-like spikes long, with six to eight whorls per centimetre, the anthers about long. Female cones are cylindrical, on a peduncle long. Mature cones are long and in diameter, the samaras dark brown to black and long.
This sheoak is similar to A. monilifera that is mostly monoecious, and lacks the "conifer-like" habit of A duncanii.

Taxonomy

Allocasuarina duncanii was first formally described in 1994 by Lawrie Johnson and Dennis Morris in the journal Telopea from specimens collected near the headwaters of the Nicholls Rivulet in 1993. The specific epithet, honours "Mr Fred Duncan", who brought the species to the attention of botanists.

Distribution and habitat

Duncan's sheoak grows in shallow soil over dolerite, usually at altitudes above, on Mount Dromedary, the Wellington Range, Snug Tiers and on South Bruny Island.

Conservation status

Allocasuarina duncanii is listed as "rare" under the Tasmanian Government Threatened Species Protection Act 1995. The main threats to the species are inappropriate fire regimes, drought and climate change.