Gluta L.

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

Distribution

A genus of about 30 species from Madagascar, Indo-China, South-East Asia and throughout Malesia. A single species in New Guinea, Gluta papuana Ding Hou, so far only known from the Western and Gulf regions of Papua New Guinea.

Morphology General Habit

Deciduous trees or shrubs to 30(–50) m tall, with dermatitis-causing exudate

Morphology Leaves

Leaves simple, spirally arranged or rarely pseudo-whorled, petiolate, rarely sessile

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, paniculate, appearing before the leaves or with new leaves

Morphology Reproductive morphology Flowers

Flowers bisexual, floral axis between calyx and ovary often elongated (forming a torus); calyx calyptriform in bud, breaking away transversally at anthesis or splitting irregularly, caducous; petals imbricate, caducous or persistent and accrescent in fruit; stamens 5 (in New Guinea), inserted on torus; disk absent; ovary sessile or stiped, 1-locular, style filiform, lateral to sublateral, stigma minutely thickened

Morphology Reproductive morphology Fruits

Fruit a drupe, globose to reniform, sometimes with wing-like persistent petals at the base.

Ecology

Found in seasonally inundated forests, along the edges of rivers and in swamps, in muddy brackish habitats and also in secondary forests; from sea level to 30 m.

Recognition

The genus can be identified by the combination of the simple leaves, bisexual flowers with 5 stamens, no disk, and especially the abundant resin that turns black on exposure to air, visible on twigs and sometimes on leaves.