Leptomischus, Drake, 1895

Anh, Tran Thi Phuong, Quang, Bui Hong, Nuraliev, Maxim S., Nguyen, Khang Sinh & Averyanov, Leonid V., 2021, Leptomischus anisophyllus (Argostemmateae: Rubiaceae), a new species from Vietnam, Phytotaxa 507 (2), pp. 198-204 : 203

Key to the species of Leptomischus in Vietnam

1. Stem with internodes less than 1 cm long, leaves crowded and rosulate ..................................................................... L. primuloides

- Stem with internodes usually more than 1 cm long, leaves distant along stem .................................................................................2

2. Leaves isophyllous (or nearly so); corolla up to 6.5 mm long ....................................................................................... L. parviflorus

- Leaves strongly anisophyllous; corolla at least 10 mm long (sometimes significantly longer).........................................................3

3. Young stem glabrous; leaf blades, petioles and stipules glabrous; flowers solitary in axils of distal foliage leaves; corolla tube 32–40 mm long....................................................................................................................................................................... L. hiepii

- Young stem pubescent; leaf blades, petioles and stipules hairy; flowers in terminal several-flowered cymes; corolla tube 10–15 mm long.............................................................................................................................................................................. L. anisophyllus