Helicia australasica

File:Helicia australasica ALA2.jpg

Inflorescences

Helicia australasica, also known as Austral oak or creek silky oak, is a species of rainforest tree in the macadamia family Proteaceae, native to New Guinea and northern and northeastern Australia.

Description

Helicia australasica is a shrub or small tree up to about Template:Cvt tall with a trunk that rarely exceeds Template:Cvt diameter. Twigs are terete (rounded) in cross-section, and younger parts – i.e. the soft non-woody parts – may be covered in fine rusty brown hairs. Older parts of twigs and branches are hairless and more or less smooth and grey. The leaf shape is variable and may be elliptic, oblong or lanceolate. Leaves are up to Template:Cvt long by Template:Cvt wide, and held on a petiole up to Template:Cvt long. They have 6–10 pairs of lateral veins that curve throughout their length, and the leaf margin is irregularly toothed.Template:R

The inflorescences are produced in the Template:Botanygloss or directly from the branches (a process called ramiflory) and may reach Template:Cvt in length. Flowers are numerous, paired, each pair sharing a branched pedicel arising from the main axis of the inflorescence. The fruit is a drupe, blue to black in colour with a smooth skin. They grow up to Template:Cvt long by Template:Cvt wide and contain a single seed up to Template:Cvt long.

Taxonomy

This plant was first described by Ferdinand von Mueller, and published in Hooker's Journal of Botany & Kew Garden Miscellany in 1857. The type species was collected in 1855 near the Macadam Range, southwest of Darwin in the Northern Territory.Template:R

Synonymy

Helicia glabrescens C.T.White (1944), and Helicia dentellata Sleumer (1939), were both placed in synonymy with H. australasica by the Australian botanist Donald Bruce Foreman in 1983,Template:R a position that is accepted by the Australian Plant Name Index.Template:R However Plants of the World Online still recognises both as distinct species.Template:R No other synonyms or infraspecies have been proposed.

Indigenous names

In the language of the Dyirbal people of northeast Queensland, this plant was known as miyabur, though the more general word gurruŋunTemplate:Snd"oak tree"Template:Sndwas used in the taboo, or Dyalŋuy, vocabulary.Template:R

Distribution and habitat

This species is naturally widespread in the "Top End" of the Northern Territory, along the east coast of Cape York Peninsula, and in south-central New Guinea.Template:R It grows alongside watercourses in drier rainforest types, at altitudes from sea level to about Template:Cvt altitude.Template:R

Conservation

There are no significant threats identified for the species, and it has been assessed as least concern under the Northern Territory's TPWCA legislation, Queensland's NCA legislation, and by the International Union for Conservation of Nature.Template:R

Cultural

The fruit was eaten raw by indigenous Australians.Template:R

External links

• View a map of herbarium records of this species at the Australasian Virtual Herbarium
• View observations of this species on iNaturalist
• See images of this species on Flickriver.com