1. Aquilaria sinensis (Loureiro) Sprengel, Syst. Veg. 2: 356. 1825.
土沉香 tu chen xiang
Ophispermum sinense Loureiro, Fl. Cochinch. 1: 281. 1790; Agallochum sinense (Loureiro) Kuntze; Aquilaria grandiflora Bentham; A. ophispermum Poiret.
Trees 5-15 m tall. Bark dark gray, smooth; branchlets terete, rugose, puberulous, glabrescent. Petiole 5-7 mm, pubescent; leaf blade dark or purple-green, glossy adaxially, light green abaxially, orbicular or elliptic to oblong, sometimes obovate, 5-9 × 2.8-6 cm, leathery, both surfaces glabrous, but sometimes puberulous along margin, base broadly cuneate, apex acuminate or acute, apiculate; lateral veins 15-20 pairs, more conspicuous abaxially, veins and veinlets slender, subparallel, obscure. Inflorescence terminal, a loose panicle of umbels, many flowered. Flowers fragrant at night; pedicel 5-10 mm, densely yellow-gray pubescent. Calyx yellowish green; tube narrowly campanulate, 5-6 mm, exterior and interior densely pubescent; lobes 5, ovate, 3-5 mm, both surfaces pubescent, apex rounded and obtuse, or acute. Petaloid appendages 10, scalelike, inserted at throat of tube, obviously densely pilose at anthesis. Stamens 10; filaments ca. 1 mm; anthers linear-oblong, ca. 1.5 mm. Ovary ovoid, densely grayish white hairy; style obsolete or nearly so; stigma capitate. Capsule shortly stipitate, ovoid, 2-3 × ca. 2 cm, densely yellow pubescent, base tapering, apex apiculate; pericarp thin, smooth when dried. Seeds dark brown, ovoid, ca. 10 × 7.5 mm, white sericeous or glabrous; funicle conspicuous, ca. 1.5 × 0.4 cm, longer than seed, tapered at base, broad and compressed below seed. Fl. spring-summer, fr. summer-autumn.
● Lowland forests, sunny places on slopes or along roadsides. Fujian, Guangdong, Guangxi, Hainan.
Aquilaria sinensis has been very heavily exploited and is listed as vulnerable by the IUCN. The bark is used to make paper; the heart wood is prized for its fragrance.