| Austral oak | |
|---|---|
 | |
| Inflorescence | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Proteales |
| Family: | Proteaceae |
| Genus: | Helicia |
| Species: | H. australasica |
| Binomial name | |
| Helicia australasica | |
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.
Helicia australasica is a shrub or small tree up to about 20 m (66 ft) tall with a trunk that rarely exceeds 30 cm (12 in) 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 23 cm (9.1 in) long by 8.5 cm (3.3 in) wide, and held on a petiole up to 10 mm (0.39 in) long. They have 6–10 pairs of lateral veins that curve throughout their length, and the leaf margin is irregularly toothed. [4] [5] [6] [7] [8]
The inflorescences are produced in the leaf axils or directly from the branches (a process called ramiflory) and may reach 17 cm (6.7 in) 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 15 mm (0.59 in) long by 11 mm (0.43 in) wide and contain a single seed up to 12 mm (0.47 in) long.
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. [9]
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, [4] a position that is accepted by the Australian Plant Name Index. [10] However Plants of the World Online still recognises both as distinct species. [11] [12] No other synonyms or infraspecies have been proposed.
In the language of the Dyirbal people of northeast Queensland, this plant was known as miyabur, though the more general word gurruŋun –"oak tree" –was used in the taboo, or Dyalŋuy, vocabulary. [13]
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. [14] [15] It grows alongside watercourses in drier rainforest types, at altitudes from sea level to about 1,100 m (3,600 ft) altitude. [4] [5] [7]
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. [1] [16] [17]
The fruit was eaten raw by indigenous Australians. [7]
Floydia is a monotypic genus of plants in the macadamia family Proteaceae which is endemic to Australia. The sole described species is Floydia praealta, commonly known as the ball nut. It is a somewhat rare tree found only growing in the rainforests of southeastern Queensland and northeastern New South Wales. The tree has a superficial resemblance to the closely related Macadamia and could be confused with them. The fruit of F. praealta is poisonous.
Athertonia is a monotypic genus of plants in the family Proteaceae. The sole described species is Athertonia diversifolia, commonly known as Atherton oak, athertonia, creamy silky oak or white oak. It is endemic to a small part of the Wet Tropics of Queensland, Australia. A relative of the macadamia, it has potential in horticulture and the bushfood industry.
Triunia is a genus of medium to tall shrubs or small trees found as understorey plants in rainforests of eastern Australia. Members of the plant family Proteaceae, they are notable for their poisonous fleshy fruits or drupes. Only one species, T. youngiana, is commonly seen in cultivation.
Helicia is a genus of 110 species of trees and shrubs, constituting part of the plant family Proteaceae. They grow naturally in rainforests throughout tropical South and Southeast Asia, including India, Sri Lanka, Indochina, Peninsular Malaysia to New Guinea and as far south as New South Wales.
Heliciopsis is a genus of about fourteen species of trees, constituting part of the flowering plant family Proteaceae. They grow naturally in Myanmar, Indo-China, China, Thailand, Peninsular Malaysia, Borneo, Sumatra, Java (Indonesia) and the Philippines. The name means similar to the plant genus Helicia. Its closest relatives are Athertonia (Australia) and Virotia.
Ficus fraseri, the white sandpaper fig or shiny sandpaper fig, is one of several fig species commonly known as sandpaper figs. It is native to the northern and eastern coasts of Australia, and to New Caledonia and Vanuatu. Other common names are "figwood" and "watery fig".
Cardwellia is a monotypic genus in the plant family Proteaceae. The sole described species is Cardwellia sublimis − commonly known as northern silky oak, bull oak or lacewood − which is endemic to the rainforests of northeastern Queensland, Australia.
Helicia glabriflora is a species of rainforest shrubs or small trees occurring in eastern Australia. Common names include smooth or pale helicia, pale, leather or brown oak. They grow naturally in a variety of different rainforest types from the Illawarra, New South Wales to the Townsville area, Queensland. Of all the global diversity of approximately one hundred Helicia species, this one species naturally grows the furthest south, in the Minnamurra Rainforest and the Robertson area, Illawarra, New South Wales, there observed more on the relatively fertile basalt and alluvial soils.
Darlingia ferruginea, commonly known as the brown silky oak, is a rainforest tree of the family Proteaceae from Northern Queensland.
Opisthiolepis is a monotypic genus of trees in the macadamia family Proteaceae. The sole species is Opisthiolepis heterophylla, commonly known as blush silky oak, pink silky oak, brown silky oak or drunk rabbit. It was first described in 1952 and is endemic to a small part of northeastern Queensland, Australia.
Catalepidia is a monotypic genus in the family Proteaceae which is endemic to Queensland, Australia. The sole described species is Catalepidia heyana, commonly known as Hey's nut oak. It is a medium sized tree growing up to about 18 m (59 ft) tall, and is found only in upland rainforest above 600 m (2,000 ft) on granite soils, ranging from the Windsor Tableland to the Atherton Tableland.
Nothorites is a monotypic genus in the macadamia family Proteaceae. The sole species, Nothorites megacarpus, is endemic to the wet tropics rain forests of northeastern Queensland, Australia.
Lasjia is a genus of six species of trees of the family Proteaceae. Three species grow naturally in northeastern Queensland, Australia and three species in Sulawesi, Indonesia. Descriptively they are the tropical or northern macadamia trees group. Lasjia species characteristically branched compound inflorescences differentiate them from the Macadamia species, of Australia, which have characteristically unbranched compound inflorescences and only grow naturally about 1,000 km (620 mi) further to the south, in southern and central eastern Queensland and in northeastern New South Wales.
Helicia ferruginea, commonly named hairy honeysuckle or rusty oak, is a species of rainforest trees, of eastern Australia, from the flowering plant family Proteaceae.
Helicia lewisensis is a species of rainforest trees, of northeastern Queensland, Australia, from the flowering plant family Proteaceae. It is endemic to the northern upland rainforests of the Wet Tropics region, from about 900 to 1,330 m altitude.
Helicia grayi, also named Gray's silky oak, is a species of rainforest trees, of northeastern Queensland, Australia, from the flowering plant family Proteaceae.
Helicia nortoniana, also known as Norton's silky oak, is a species of tree in the family Proteaceae growing to about 20 m (66 ft) tall. It is endemic to the rainforests of the Wet Tropics region of Queensland, Australia, and occurs at altitudes from sea level to about 1,000 m (3,300 ft).
Isopogon linearis is a small shrub in the family Proteaceae that is endemic to the southwest of Western Australia.
Donald Bruce Foreman was an Australian botanist who worked on the Monimiaceae and Proteaceae of Australia. He also helped with the editing of selected Flora of Victoria and Flora of Australia Volumes.
Pseuduvaria glabrescens is a small tree in the custard apple family Annonaceae endemic to a very small part of coastal Queensland, Australia. It was first described as a variety of Pseuduvaria mulgraveana, and later raised to species status.
