Breynia J.R.Forst. & G.Forst.

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

Distribution

A genus of approximately 30 species from India to Australia and New Caledonia, throughout Malesia with at least ten species in New Guinea, with most becoming small trees.

Morphology Leaves Stipules

Stipules triangular, early to late caducous

Morphology Leaves

Leaves distichous, simple, symmetric, margins entire, drying blackish above, dirty brownish and often glaucous-papillate below, venation pinnate; petioles very short or leaves subsessile

Morphology General Habit

Plants monoecious Shrubs to trees to 8 m in New Guinea. Hairs simple or absent

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, fasciculate, pistillate flowers at the distal end of branches, staminate flowers at lower nodes

Morphology Reproductive morphology Flowers

Staminate flowers: calyx thin to very thick, fused at the base and obconic or turbinate; stamens 3, united into central column (androphore), anther bi-loculate longitudinally adnate to the column; pistillode absent. Pistillate flowers: calyx persistent; ovary 3-locular, stigmas 3, simple or bifid Flowers pedicellate; calyx urceolate, 6-lobed; petals and disk absent

Morphology Reproductive morphology Fruits

Fruits dehiscent capsule, ovoid, smooth, glabrous, woody, sometimes slightly fleshy outside, red when mature

Morphology Reproductive morphology Seeds

Seeds sharply trigonous, smooth, with yellow to reddish sarcotesta.

Ecology

Breynia species are found in a variety of habitats including primary and secondary lowland forest, river banks, submontane forest, old gardens etc., from sea level to 2200 m.

Recognition

The genus is recognised by the simple, alternate, distichously arranged leaves (usually relatively small), the fasciculate inflorescences, stamens united into a column, and the drupaceous fruits. The genus Sauropus is now considered within Breynia (see van Welzen (ed.) Flora Malesiana Euphorbiaceae). Airy Shaw (1980) kept them distinct noting that Breynia is very similar to Sauropus, but differing in drying black, and the stamens united into a column or rod along with the anthers.

Euphorbiaceae, A. R.-Smith. Flora of Tropical East Africa. 1987

Morphology General Habit

Monoecious or apparently dioecious shrubs or small trees with or without a simple indumentum, often blackening on drying

Morphology Leaves

Cataphylls present, as in Phyllanthus (q.v.) Leaves alternate, shortly petiolate, stipulate, simple, entire, penninerved, arranged on shoots of limited growth (plagiotropic)

Morphology Reproductive morphology Flowers

Flowers axillary, the males fasciculate or solitary in the proximal axils, the females solitary in the distal axils Female flowers: pedicels capillary or not; calyx-lobes 6, imbricate, not inflexed, usually larger than those of the ♂ flower, accrescent; disc 0; ovary 3-locular, with 2 ovules per locule; styles 3, free, short, erect, simple or bifid Male flowers: pedicels often capillary; calyx obconic or turbinate; calyx-lobes 6, imbricate, the distal halves sharply inflexed with their apices almost touching the androecium; petals 0; disc 0; stamens 3, united to form a short column, anthers elongate, the thecae linear, extrorse, adnate to the column, longitudinally dehiscent; pistillode 0

sex Male

Male flowers: pedicels often capillary; calyx obconic or turbinate; calyx-lobes 6, imbricate, the distal halves sharply inflexed with their apices almost touching the androecium; petals 0; disc 0; stamens 3, united to form a short column, anthers elongate, the thecae linear, extrorse, adnate to the column, longitudinally dehiscent; pistillode 0

sex Female

Female flowers: pedicels capillary or not; calyx-lobes 6, imbricate, not inflexed, usually larger than those of the ♂ flower, accrescent; disc 0; ovary 3-locular, with 2 ovules per locule; styles 3, free, short, erect, simple or bifid

Morphology Reproductive morphology Fruits

Fruit tardily and often incompletely loculicidally dehiscent; exocarp sometimes somewhat fleshy; endocarp crustaceous

Morphology Reproductive morphology Seeds

Seeds trigonous, ecarunculate.