5. Tetradium trichotomum Loureiro, Fl. Cochinch. 1: 91. 1790.
牛枓吴萸 niu dou wu yu
Ampacus trichotoma (Loureiro) Kuntze; Brucea trichotoma (Loureiro) Sprengel; Euodia colorata Dunn; E. hainanensis Merrill; E. lenticellata C. C. Huang; E. trichotoma (Loureiro) Elmer; E. trichotoma var. pubescens C. C. Huang; E. viridans Drake.
Shrubs or trees, to 8 m tall. Leaves 12-37 cm, (3 or)5-11(or 13)-foliolate; leaflet blades elliptic-oblong, lanceolate, or occasionally ovate, 3-16 × 3-5 cm, abaxially neither glaucous nor papillate, secondary veins 11-14 on each side of midvein, reticulate veinlets abaxially inconspicuous, margin entire, base in lateral leaflets subrounded to cuneate and in terminal leaflet cuneate, apex acuminate. Inflorescences 5-30 cm. Flowers 4(or 5)-merous. Sepals 0.5-1 mm. Petals green, yellow, or white but drying brown to whitish, 3-4 mm, outside glabrous, inside glabrous or sparsely villosulous. Ovary glabrous or with a few short trichomes between carpels toward base; ovules 2 per carpel, collateral. Fruit (including abortive carpels, if any) usually 4-carpelled; follicles subglobose to obovoid, 4-7 mm, glabrous or laterally with sparse pubescence toward base, apex not beaked; endocarp glabrous. Seeds 1 per follicle but paired with an abortive seed, subglobose to broadly ovoid, 3.7-6 mm, attached in dehisced follicle to axile strip of pergamentaceous pericarp tissue; seed coat with thick inner layer of dense black sclerenchyma and spongy outer layer bounded externally by a shiny black pellicle. Fl. Apr-Aug, fr. Sep-Nov.
Forests, thickets; 300-1900 m. SE Guangdong, Guangxi, S Guizhou, Hainan, Hubei, Shaanxi, S Sichuan, Yunnan [Laos, Thailand, N Vietnam].