Sohmaea H.Ohashi & K.Ohashi (2018b: 159)

Saisorn, Witsanu & Chantaranothai, Pranom, 2022, A taxonomic revision of two genera, Pleurolobus and Sohmaea (Leguminosae) in Thailand and Indo-China, Phytotaxa 573 (2), pp. 231-246 : 236-237

2. Sohmaea H.Ohashi & K.Ohashi (2018b: 159) .

Type: Sohmaea laxiflora (DC. 1825a: 100) H.Ohashi & K.Ohashi (2018b: 162) .

Uraria subgen. Desmodiastrum Schindler (1925: 15) . Type: Uraria henryi Schindl. (1925: 15) .

Desmodium subgen. Desmodium sect. Angustistipulosa H. Ohashi (1973: 97) . Type: Desmodium laxiflorum DC. (1825a: 100) .

Herbs to shrubs. Leaves uni- or trifoliolate, petiolate, stipulate; leaflet coriaceous, petiolulate, stipellate, lateral veins reaching the margin. Inflorescences pseudoracemose, simple or occasionally paniculate, terminal or axillary; primary bract 1, caducous; secondary bract 1, caducous. Flowers papilionaceous, pedicellate; bracteole 1 or absent; calyx connate with 4 teeth; corolla 5, with 1 standard, 2 wings and 2 connate keels; stamens 10, diadelphous; ovary unicarpellate. Pods leguminous, with a terete, oblong article; seeds rim-arillate.

Seven species distribute in Africa ( Senegal and Burkina Faso), India eastward toward China, Myanmar through mainland southeast Asia, and Malesia. Five species are indigenous to Thailand, Laos, Cambodia, and Vietnam.

Key to the species

1. Primary bracts bearing 2-fascicled flowers. Immature pods plicate ............................................................................... 2. S. hispida

1. Primary bracts bearing 3–5-fascicled flowers. Immature pods straight

2. The length of terminal leaflets 2.2–3.6 times longer than width

3. Petioles less than 1 cm long. Pod articles less than 0.7 cm long....................................................................4. S. teres

3. Petioles more than 1 cm long. Pod articles more than 0.7 cm long ............................................................5. S. zonata

2. The length of terminal leaflets less than 2 times of width

4. Flowers ca. 5 mm long. Pod articles 4–6 mm long ...................................................................................1. S. diffusa

4. Flowers 4–4.5 mm long. Pod articles 3–4.5 mm long............................................................................ 3. S. laxiflora