Lasianthus tetragonus Zhu (2001:142)

Napiroon, Tiwtawat, Chayamarit, Kongkanda, Dawson, Sally, Till, Walter & Balslev, Henrik, 2020, A synopsis of Lasianthus (Lasiantheae, Rubiaceae) in Thailand and two additional new species, Phytotaxa 439 (1), pp. 1-38 : 32

63 Lasianthus tetragonus Zhu (2001:142) . Type: ― THAILAND. Pattani, Sai Khao National Park , 16 July 1993, C. Puff & K. Sridith 930716-1/3 (holotype AAU!; isotypes BKF!, PSU!, WU!).

T hailand: ―Only known from the type collection.

Distribution: ―Endemic to Thailand (Peninsular).

Ecology: ―Moist evergreen forest, in shaded places at an elevation of 250‒ 400 m. Flowering and fruiting in June‒July.

Notes: ― Lasianthus tetragonus is similar to L. foxworthyanus but differs by having puberulous (not densely appressed-pubescent) branches and branchlets, leaves elliptic or oblong-elliptic (not oblong, oblong-lanceolate or oblong-elliptic), 8.5‒11 × 3‒4 (not 9‒16 × 3‒5) cm, adaxially glabrous, abaxially puberulous (not appressed-pubescent), petioles 10 (not 5–7) mm long, stipules triangular-lanceolate, 2.5‒3 mm (not 4‒5) mm long, and it has fresh fruits that are black (not blue or dark blue), its drupes are tetragonal (not globose).