圆叶澳杨 yuan ye ao yang

Mappa fastuosa Linden, Belg. Hort. 15: 100. 1865; Carumbium fastuosum (Linden) Müller Argoviensis; Homalanthus alpinus Elmer; H. bicolor Merrill; H. milvus Airy Shaw.

Trees or treelets, 8-18 m tall, often much branched apically, glabrous. Leaves often fascicled at apex of branch; stipules 1.5-8.5 cm; petioles 5-9 cm, reddish, with a pair of abaxial-lateral glands; leaf blade rhomboid-ovate or triangular-ovate, 4-23 × 3.5-24 cm, papery to leathery, adaxially green, abaxially glaucescent, with 0-17 laminar glands below, base obtuse or attenuate to shallowly retuse, peltate or not, apex shortly acuminate; midvein elevated abaxially, lateral veins 7-15 pairs, reticulate veins prominent. Inflorescences 12-20 cm, bisexual, female in lower part, male in upper part. Male flowers usually 3 per bract; bracts each with one pair of basal glands; glands orbicular, ca. 1.2 mm in diam.; pedicels 1.5-4 mm; calyx 2-lobed, free, lobes reniform, apex rounded; stamens 9; filaments shorter. Female flowers: pedicels 4-5 mm (elongating to 13 mm in fruits); glands orbicular; calyx 2-lobed, lobes ovate, ca. 1 mm in diam.; ovary elliptic, with 2 locules; styles 2, free; stigmas ca. 2 mm, recurved, undivided to rarely divided, with small apical glands. Capsules obovoid to subglobose, 4-6 × 6-8 mm, papillate, keeled. Seeds 3-5 × 3-4 mm, upper half or more covered by arillode.

Lowland forests. ?Hainan, Taiwan (Lan Yu) [Philippines].

The name Homalanthus alpinus was formerly used for plants with nonpeltate leaves that in all other characters are identical with H. fastuosus. The identity of plants so named from Hainan is uncertain; it is possible that they do not belong to this genus.