Trigonostemon viridissimus var. elegantissimus, (Airy Shaw) Airy Shaw

Yu, R. - Y. & Welzen, P. C. van, 2018, A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia, Blumea 62 (3), pp. 179-229 : 222

b. var. elegantissimus (Airy Shaw) Airy Shaw — Map 14

Trigonostemon viridissimus (Kurz) Airy Shaw var. elegantissimus (Airy Shaw) Airy Shaw (1975) 206. — Trigonostemon elegantissimus Airy Shaw (1966) 48; (1978) 417; Whitmore (1973) 135; R.I. Milne (1995a) 28, in key, 29, in key, 47. — Type: Kostermans 13695 (holo K; iso A*, BO, K, L), E Kalimantan, Sangkulirang District, Karangan River, near Batu Pondong.

Trigonostemon sanguineus Gagnep. (1925a) 470. — Type: Poilane 8201 (K, P), Vietnam, km 26 route from Nhatrang to Ninh Hoa.

Leaves: petiole 1.5–5.5 cm long, glabrous to slightly pubescent; blade oblong to lanceolate, glabrous above, glabrous to sparsely pubescent beneath. Inflorescences often terminal or subterminal, erect and firm, glabrous.

Distribution — Vietnam, Malay Peninsula, Borneo.

Habitat & Ecology — Growing on sandy loam to sandy stone. Altitude: 170– 230 m. Flowering: March to September; fruiting: July, October.

Note — The form elegantissimus is here recognized as a variety, following Airy Shaw (1975). The two varieties closely resemble each other in their floral structures, like the contort petals, the slender long and only shortly bifid stigmas. The length of the petiole and the shape of the leaf blade also show some overlap. Milne (1995a) presents a good discussion on the differences between the two varieties although he treated them as two separate species.