Aporosa octandra is a species of plant in the family Phyllanthaceae found from Queensland and New Guinea to Indonesia, China and India.
There are four accepted varieties:[2][9][8] The species was described in 1982 by the botanist Albert Roy Vickery, in the publication An Enumeration of the Flowering Plants of Nepal (London), which was a joint project of the British Museum (Natural History) and the University of Tokyo.
The varieties were first described by Anne M. Schot in 1995 in the article A synopsis of taxonomic changes in Aporosa Blume (Euphorbiaceae), published in the journal Blumea.
[citation needed] The bark is a light-brown to grey or tan, can be either smooth, roughened, thickened, flaky or with narrow vertical ridges and cracks.
Pistillate inflorescences occur as 1 to 3 clustered together, with up to 11 densely arranged flowers along the rachis, 4 sepals, occasionallyy staminodes, slightly raised and elongated stigmas, perpendicular to the sides of the ovary.
The leathery leaf blade ranges from elliptic to narrowly ovate, oblong-elliptic, obovate and oblanceolate, is 6-12 x 3.5-6cm in size, glabrous and adaxially lucid, is sparsely pubescent abaxially along nerves, has a round or cuneate base with an entire or sparsely shallowly dentate margin, and rounded to acute apex.
The female flowers have 4-6 triangular sepals with ciliate margins, ovoid ovary which is densely pubescent and bilocular, with 2 ovules per locule.
Tomentose branchlets; narrowly ovate to same elliptic leaves with a (lowly) glandular-serrate margin, thin and slightly shiny leaf, drying greyish to brownish both sides, sparsely puberulous, with puberulous midrib and nerves on underside; the flowers are pistillate with a tomentose ovary.
[2] Countries and regions in which it is native to include: Australia (Queensland); Papua New Guinea; Indonesia (West Papua, Sulawesi, Kalimantan, Java, Sumatra); Philippines; Malaysia (Sabah, Sarawak, Peninsular Malaysia); Thailand; Cambodia; Vietnam; China (Hainan, South-Central, Southeast); Laos; Myanmar; India (Nicobar Islands, Andaman Islands, Assam, Nagaland, Manipur, Mizoram, Tripura, Meghalaya, Sikkim, West Bengal, Odisha, Uttarakhand); Bangladesh; East and West Himalaya; Bhutan; Nepal.
The species grows in a variety of habitats: primary, secondary, subtropical, evergreen, and (mixed) deciduous forests, savannah, belukar (low forest/scrub, perhaps anthropogenic), moist to rather dry.
The tree tends to be a gallery species, favouring hills, (steep) slopes, forest edges, road sides, plains, thickets and alongside watercourses.
yunnanensis is locally dominant in the bamboo-deciduous forest, alongside Cananga brandisiana, Croton persimilis, Gardenia sootepensis, Lagerstroemia sp., Colona flagrocarpa and Pterocarpus macrocarpus.
[17] In the medium layer of the forest (some 6-9m tall), the varieties octandra and yunnanensis are common, along with Quercus kerrii, Memecylon scutellatum, Harrisonia perforata and a dense bamboo understory.
The yunnanensis variety grows in evergreen forest; in soils derived from granite bedrock; at elevations of 1100 to 1450m; and has leaves from April to December.
On the islands of the Mekong river in Kratié and Steung Treng Provinces, northern Cambodia, the variety yunnanensis is moderarately common in dipterous deciduous forest, and also occurs in degraded areas and secondary growth communities.
[16] In India it is commonly found in primary forests and grasslands, growing on sandy, clay or rocky soil, at up to 1200 m altitude.
[citation needed] Mizoram University (India) is embedded in a regenerating tropical wet evergreen and semi-evergreen forest.
The dominant trees of this forest are Schima wallichii, Aporosa octandra, Castanopsis tribuloides, and Syzgium praecox.
[19] The now regenerating forests of Hong Kong were heavily degraded in the 19th and early 20th centuries with the most impact occurring during World War II (here 1941-5).
[1] This is because the tree has a very wide distribution with a large population and that it is not at the moment and foreseeable future experiencing any major threats.
[25][24] In Cambodia the bark is a component of a folk-remedy to relieve tooth-ache, while the roots are used in another folk-medicine mixture to be used "against women diseases after delivery".