Citrus buxifolia Poiret, Encycl. 4: 580. 1797; Dumula sinensis Loureiro ex B. A. Gomes; Limonia monophylla Loureiro (1790), not Linnaeus (1767); Severinia buxifolia (Poiret) Tenore; S. monophylla Tanaka.

Shrubs ca. 2.5 m tall. Branches grayish brown; branchlets green, with spines or rarely unarmed; spines ca. 4 cm, apex red. Leaves simple; petiole 1-7 mm; leaf blade ovate, obovate, elliptic, or suborbicular, 2-6(-10) × 1-5 cm, leathery, with oil glands and an orange smell, midvein slightly ridged, secondary veins joined in an arched marginal vein, apex rounded to obtuse and retuse to emarginate at tip. Inflorescences axillary, fasciculate, (1- or) several flowered. Flowers 5-merous, subsessile. Calyx persistent. Petals white, 3-4 mm, with oil glands. Stamens 10; filaments white, distinct or sometimes a few basally connate. Style green, ± as long as ovary. Fruit bluish black when ripe, globose, slightly oblate, or subellipsoid, 0.8-1.2 cm in diam., smooth, 1- or 2-seeded. Seeds with 1(or 2) embryos; cotyledons green, with many oil glands. Fl. May-Dec, fr. Sep-Dec. 2n = 36.

Forests or thickets near ocean; below 300 m. S Fujian, S Guangdong, S Guangxi, Hainan, S Taiwan, Yunnan [Malaysia, Philippines, Vietnam].