Kayea Wall.

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

Distribution

A poorly known and rarely collected genus of about 70 species with a distribution from India to Australia. Two species in New Guinea, both have been placed in Mesua L., but that genus does not reach New Guinea, see Stevens (1993, 2007): Kayea coriacea (P.F.Stevens) P.F.Stevens and K. macrophylla Kanehira & Hatusima.

Morphology General Habit

Trees to 20 m tall

Morphology General Exudate

Exudate usually present, often varnish-like in dry material-Stem often papillate, terminal bud with scales

Morphology Leaves

Leaves opposite, coriaceous, glabrous, lacking free glands or canals, midrib darker than lateral veins, lateral veins usually ascending, sometimes brochidodromous

Morphology Reproductive morphology Inflorescences

Inflorescence terminal or axillary, compound cymes, few–many-flowered

Morphology Reproductive morphology Flowers

Flowers with 2 pairs of decussate sepals; petals 4; anthers <1 mm long, with or without a terminal gland; ovary 1-locular with 4–8 ovules, style long, shortly branched at the apex (usually into 4 arms), stigma punctate, placentation basal-Fruit a subglobose capsule, almost completely enclosed by the accrescent calyx

Morphology Reproductive morphology Seeds

Seeds 1–2 (in New Guinea)

Recognition

Useful characters to distinguish Kayea are the branched inflorescence axis and the accrescent calyx. The secondary venation is not distinctly parallel like Calophyllum or highly reticulate like Mammea. The opposite leaves, many stamens and the looping marginal vein might cause confusion with Syzygium (Myrtaceae), but Syzygium does not have exudate from cut stems, a superior ovary or a branched style.