1. Trivalvaria costata (J. D. Hooker & Thomson) I. M. Turner, Kew Bull. 64: 577. 2009.
海岛木 hai dao mu
Guatteria costata J. D. Hooker & Thomson, Fl. Ind. 1: 143. 1855; Ellipeia costata (J. D. Hooker & Thomson) King; Polyalthia costata (J. D. Hooker & Thomson) J. D. Hooker & Thomson; P. nemoralis Aug. Candolle; P. oligogyna Merrill & Chun.
Shrubs or small trees, to 5 m tall. Branches densely to very sparsely pubescent when young, glabrescent. Petiole 2-10 mm, densely pubescent to glabrous; leaf blade obovate to elliptic to (ovate-)oblong, 6-25 × 2-9 cm, membranous to thinly leathery, abaxially sparsely to densely pubescent, adaxially glabrous or rarely pubescent, base cuneate to ± rounded, apex acuminate to caudate, sometimes rounded, midvein adaxially impressed, lateral veins adaxially faint to indistinct. Inflorescences extra-axillary or sometimes ± leaf-opposed, rarely from old branches, often on woody axis with scars of previous flowers, 1- or 2-flowered; bracts 1 or 2, triangular to ovate, 1.5-3(-5) mm. Flowers polygamous (male and bisexual). Pedicel 2-5(-8) mm, pubescent. Buds 2.5-5(-8) mm. Sepals triangular to very broadly ovate, 2-3.5 × 1.5-4 mm, outside densely pubescent, apex acuminate to rounded. Petals white to dirty pale yellow, minutely imbricate, (ob)lanceolate, narrowly ovate to broadly triangular, 2-8(-12) × 1-4.5 mm, spreading outside pubescent, inside glabrous; inner petals obovate to lanceolate, 4-12 × 1-4 mm, apex rounded to bluntly acute. Male flowers: torus conical; stamens many, 1.3-2.6 mm; connective apex shieldlike, sometimes tongue-shaped on outer stamens, glabrous or densely puberulent. Bisexual flowers: torus cylindrical; stamens many; carpels 2-10, densely hairy; stigma pubescent. Fruiting pedicel 3-5(-8) mm; monocarp stipes 1-6 mm; monocarps to 5, sometimes glaucous, ripening red, ellipsoid to oblong, 10-28 × 5-11 mm, sparsely pubescent, verruculose, with circumferential longitudinal groove.
Hainan [India (Andaman Islands), Laos, Malaysia, Myanmar, Thailand, Vietnam].
The Chinese material of Trivalvaria costata was included within Polyalthia nemoralis (as the synonym P. oligogyna) in FRPS (30(2): 87. 1979). "Polyalthia dubia" (Kurz, Rep. Veg. Andaman Isl. 29. 1870) belongs here but is a nomen nudum and was therefore not validly published (Vienna Code, Art. 32.1(d)); as a result,"P. dubia var. glabriuscula" (Kurz, J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 43(2): 53. 1874) was also not validly published (Art. 43.1). Popowia kurzii King (J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 61(2): 96. 1892) was also applied to this species, but that name was nomenclaturally superfluous (and is therefore illegitimate: Art. 52.1), because the earlier name Guatteria macrophylla Blume was cited as a synonym in the protologue.