Chydenanthus Miers

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

Distribution

A monotypic genus with a single species from the Andaman Islands and lower Myanmar through Malesia and reaching New Guinea: Chydenanthus excelsus (Blume) Miers.

Morphology General Habit

Trees to 10 m (reaching 20 m in cultivation)

Morphology Leaves Stipules

Stipules minute, caducous

Morphology Leaves

Leaves spirally arranged, well-spaced along the twigs, margins entire or faintly serrulate

Morphology Reproductive morphology Inflorescences

Inflorescences terminal, many-flowered, paniculate

Morphology Reproductive morphology Flowers

Flowers sessile, 3–4-merous; hypanthium ellipsoid, smooth; calyx of 3–4 persistent lobes; petals 4, loosely attached to the staminal tube; stamens numerous in several whorls, inner whorl of staminodes, shortly connate at the base into a tube, stamens and staminodes caducous as a whole; disk intrastaminal, annular; ovary inferior, 2-locular, ovules 2 per locule, placentation central; style filiform, as long as stamens

Morphology Reproductive morphology Fruits

Fruit ovoid, ellipsoid to obovoid or globose, not winged or ribbed

Morphology Reproductive morphology Seeds

Seed 1; embryo large, cotyledons absent.

Ecology

Chydenanthus excelsa is poorly known from New Guinea but in South-East Asia is found in lowland habitats especially wet forest areas from sea level to 50 m.

Recognition

The genus is similar to Barringtonia in sharing the single seed per fruit which lacks cotyledons, but differs in the well spaced leaves (rather than in whorls), the paniculate inflorescences and pubescent flowers and the fruit which is not winged or ribbed. Prance & Kartawinata (2013) note that the genus has very small subulate stipules at the base of the leaves which are only discernable in very young leaves.