Trigonostemon angustifolius Merr.

Yu, R. - Y. & Welzen, P. C. van, 2018, A taxonomic revision of Trigonostemon (Euphorbiaceae) in Malesia, Blumea 62 (3), pp. 179-229 : 224

35. Trigonostemon angustifolius Merr. — Map 15

Trigonostemon angustifolius Merr.(1922) 396. — Type: BS ( Ramos & Edaño) 36764 (of 36560) (holo PNH†; iso A, K, US), Philippines, Mindanao, Zamboanga District, Malangas .

Shrubs, 1–3 m tall; flowering branches c. 3 mm diam. Outer bark c. 0.1 mm thick, white to grey, smooth, slightly pubescent when young, glabrescent; inner bark 0.2–0.3 mm thick, dark brownish; wood white to yellow. Stipules very small, pointing, appressed pubescent, caducous. Leaves: petiole terete but grooved above, 5–8 mm long, 1.2–1.5 mm diam, appressed pubescent; blade oblong, 10–15 by 2–3 cm, chartaceous, base acute, glands not seen, margin distantly serrate, teeth glandular, apex acuminate to shortly caudate, upper surface dark brown to black (when dry), glabrous, lower surface reddish brown, slightly pubescent; midrib slightly raised and glabrous above, distinctly elevated and pubescent beneath, nerves 8 –11 pairs, pubescent beneath, veins reticulate, obscure above. Inflorescences: staminate ones not seen; pistillate ones axillary, slender, peduncled, a glomerule at apex; peduncle c. 5 cm long, c. 0.5 mm diam, appressed pubescent; glomerules few-flowered, subtended by two bracts (also one bract present on the lower node), bracts lanceolate, 10–12 by 2–3 mm, appressed pubescent beneath. Staminate flowers not seen. Pistillate flowers: sepals lanceolate, c. 6 by 2.5 mm, apex acuminate, outside eglandular, slightly pubescent; petals 5–6 mm long, glabrous, dark purple; ovary glabrous, styles 3, stigmas cleft nearly to the base, arms linear, 1.5 mm long, acuminate. Fruits depressed globose, c. 12 mm diam, brown, sparingly appressed pubescent, sepals accrescent up to 12 by 6 mm. Seeds not seen.

Distribution — Philippines (Mindanao, endemic).

Habitat & Ecology — On forested slopes at low altitudes ( Merrill 1922). Flowering: October.

Vernacular name — Pululi ( Merrill 1922).

Note — The species is only known from the type collection. Due to the insufficient material seen the descriptions of pistillate flowers and fruits are based on Merrill (1922). Knowledge on the staminate flowers of the species is still lacking and, therefore, it is impossible to even determine whether the species belongs to Trigonostemon or not.