Lophopetalum Wight ex Arn.

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

Distribution

Genus of c. 20 species from India and Indo-China throughout Malesia except for Java and the Lesser Sunda Islands; five species in New Guinea.

Morphology General Habit

Small to tall trees to 45 m, sometimes with buttresses

Morphology Leaves Stipules

Stipules a tuft of hair-like processes, caducous

Morphology Leaves

Leaves decussate, or opposite, sometimes subopposite (occasionally some leaves spirally arranged), margins entire

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, thyrsoid

Morphology Reproductive morphology Flowers

Flowers bisexual, 5-merous (except the ovary); calyx dish-shaped, lobes rounded or triangular; petals imbricate, inner surface usually partly covered with appendages; stamens inserted on the disk, sometimes near the margin, filaments filiform, anthers usually broad-ovoid or -ellipsoid, versatile, ±introrse; disk usually fleshy and ±flat, 5-angular, ±rounded, or distinctly 5- lobed; ovary 3-celled, usually partly immersed in the disk, trigonal; ovules 4–18 per cell, arranged in 2 series; style short, cylindric; stigma obscure

Morphology Reproductive morphology Fruits

Fruit a loculicidally dehiscent capsule, oblong, or slightly spindle-shaped, 3-lobed, -winged, or -angled. Seeds oblong, flat, attached in the middle, the wing surrounding the seed.

Ecology

Found in a variety of habitats, including primary rain forest, swamp forest and more rarely secondary forest, usually in the lowlands but up to 2200 m.

Recognition

Members of Lophopetalum are usually large trees, and distinct because of the decussate or opposite leaves, the flowers with 5 calyx, petals and stamens, the appendages on the inner surface of the petals, the usually 5-lobed disk, and the 3-celled ovary which is often trigonal in shape, and the dehiscent fruit with flattened seeds with a wing surrounding the seed. Sterile specimens are difficult to name to species, but the leaves often dry brown or dark-brown (in contrast to many Celastraceae which dry a grey-green).