Aporosa Blume

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Distribution

A genus of at least 80 species from India and Sri Lanka to China and Indo-China, throughout Malesia to the western Solomon Islands; at least 22 species in New Guinea, all of which can be trees.

Morphology General Indumentum

Hairs simple

Morphology Leaves Stipules

Stipules narrowly triangular, persistent or caducous

Morphology Leaves

Leaves alternate, simple, blade symmetric, basally often 2 glands, margin entire to serrate or crenate, venation pinnate, nerves looped and closed near margin; petiole pulvinate at base and apex

Morphology General Habit

Plants dioecious Trees to 25 m in New Guinea

Morphology Reproductive morphology Inflorescences

Inflorescences simple, thyrsoid spikes, axillary (to ramiflorous), single to many together; staminate glomerules and pistillate flowers spirally arranged; bracts 1 per glomerule or pistillate flower

Morphology Reproductive morphology Flowers

Staminate flowers: stamens 2–4, episepalous, not to strongly exserted; pistillode absent or present Flowers pedicelled or not; sepals 3–6; petals absent; disk absent

Morphology Reproductive morphology Flowers Gynoecium Pistil

Pistillate flowers: ovary 2- or 3(4)-locular; style absent; stigmas apically lobed to completely divided

Morphology Reproductive morphology Fruits

Fruits a dehiscent capsule (sometimes tardily), sometimes beaked and/or stiped, or with ridges along sutures

Morphology Reproductive morphology Seeds

Seeds with only 1 per locule developing, ovoid to ellipsoid, covered with a thin, fleshy, juicy, yellow, orange to red aril.

Ecology

The genus is found as substage and understorey trees and shrubs as well as subcanopy trees in a variety of habitats including primary and secondary lowland and montane forests, as well as regrowth; from sea level to 2100 m.

Recognition

Aporosa can be recognised by the alternate leaves with relatively short petioles which are pulvinate at the base and apex, spicate or racemose inflorescences, staminate flowers with only 2–4 stamens and lacking a pistillode, pistillate flowers without any style but with distinct stigmas which can be elongated and branched, the dehiscent fruits topped with the persistent stigmas. Airy Shaw (1980) notes it is similar to Baccaurea but differs from that genus in the minute staminate flowers which are densely crowded in spicate inflorescences and the dehiscent fruits.