Tetradium ruticarpum (A. Juss.) T. G. Hartley in Gard. Bull. Straits Settlem. 34: 116. 1981. Boymia rutaecarpa A. Juss. in Mem. Mus. Hist. Nat. 12: 507, t. 25, f. 39. 1825 & Mem. Rutaceae 124: t, 25. f. 30, 1825. Euodia rutaecarpa (A. Juss.) Benth., Fl. Hongkong 59. 1861; Hook.f., Fl. Brit. India 1: 490. 1875.

Shrubs or moderate trees up to 10 m high; branchlets stout, glabrate to finely velvety; bark deep brown, lenticellate. Leaves 20 - 31 cm long; rachis strong, terete, velvety-pubescent; leaflets 6 - 12, rarely if 3, then 7 - 13-foliolate leaves on same branchlet, opposite or subopposite, ovate, oblong, oblong-lanceolate, base in lateral leaflets obtuse to rounded and oblique, cuneate in terminal ones, apex acute or shortly acuminate, margins entire, 5 - 17 x 2.5 - 5.8 cm, chartaceous, pale or brown beneath when dry, glaucous, velvety-pubescent or densely woolly beneath, shortly pubescent above; secondary nerves 10 - 16 pairs, faint, slightly arching; petiolules of lateral leaflets subsessile or up to 7 mm long, terminal leaflets on an extension of rachis 15 - 20 mm long. Panicles 6 - 12 cm long; peduncle and branches stout, velvety-pubescent; pedicels ca 2 mm long, pubescent. Flowers predominantly 5-merous, occasionally 4-merous, ca 5 mm long, ca 8 mm across. Male flowers: Sepals connate at base, ovate, obtusely acuminate, ca 1 mm long, pubescent. Petals oblong, obtuse, 3.5 - 4 mm long, glabrous abaxially, villous adaxially along midnerve. Stamens 5; filaments subulate, 1.5 - 2 mm long, hairy adaxially; anthers ca 2.5 mm long, ovoid. Pistillodes usually 5, connate at base, 3 - 3.5 mm long, glabrous or sometimes hairy. Disk obscure. Female flowers: Sepals, petals and disk as in male flowers. Ovary 4- or 5 carpellate, glabrous or sparsely hairy, punctate, 4- or 5-locular, ovules 2 per locule, collateral; style very short; stigma capitate. Follicles globose or subglobose, 4 - 6 mm long, ca 1 mm across, glabrous or sparsely pubescent, glandular-punctate or pustular, 1-seeded, paired with an aborted seed; seeds ellipsoid, 3 - 5 mm long, ca 4 mm across, brown, rugose.

Fl. May - June; Fr. July - Sept.

Distrib. India: Temperate forests in Sikkim Himalayas and Khasi hills, 1750 - 2500 m. Sikkim and Meghalaya.

Bhutan, China and Japan.

Notes. The Chinese drug Wou-Tchou-Yer, which is used extensively as a stimulant, carminative and stomachic, is extracted from dried fruits of this plant.

T. ruticarpum can easily be distinguished from other species of the genus in having velvety-pubescence all over the plant, very stout branches of panicles, and pustular fruits.