1. Desmanthus pernambucanus (Linnaeus) Thellung, Mém. Soc. Sci. Nat. Math. Cherbourg, sér. 4. 38: 256. 1912.
合欢草 he huan cao
Mimosa pernambucana Linnaeus, Sp. Pl. 1: 519. 1753.
Subshrubs, to 2 m tall. Stem glabrous or slightly puberulent, angulate. Stipules subulate; petiolar gland on lowest pair of pinnae; pinnae 2-6 pairs, 1.2-2.5 cm; leaflets 6-21 pairs per pinna, oblong, 4-6 × ca. 2 mm, ciliate along margin, slightly asymmetric, base truncate, apex acute. Heads axillary, ca. 5 mm in diam., 4-10-flowered; bracteoles ovate, caducous. Flowers white, upper ones bisexual, lower ones male. Calyx campanulate, ca. 2.5 mm, 5-dentate. Petals 5, narrowly lanceolate, 3-4 mm. Stamens 10, ca. 5 mm, free. Ovary oblong, ca. 2 mm. Legume reddish brown, straight or slightly curved, linear, 4-11 × 0.2-0.4 cm. Seeds dark brown, rectangular, ca. 3 mm.
Naturalized in Guangdong, Taiwan, Yunnan [native to tropical America; widely cultivated in the tropics].
In FRPS (39: 20. 1988), the name Desmanthus virgatus (Linnaeus) Willdenow was misapplied to this species.
This species is planted as a cover crop.