Trigonostemon semperflorens (Roxb.) Müll.Arg.

Yu, R. - Y. & Welzen, P. C. van, 2020, A taxonomic revision of Trigonostemon (Euphorbiaceae) outside Malesia, Blumea 65 (1), pp. 25-52 : 43

26. Trigonostemon semperflorens (Roxb.) Müll.Arg. — sect. Trigonostemon — Map 7

Trigonostemon semperflorens (Roxb.) Müll.Arg. (1866) 1110;Hook.f. (1887) 397; Brandis (1906) 580; Pax & K.Hoffm. (1911) 90; Kanjilal et al. (1940) 196; N.P.Balakr. (1983) 427. — Clutia semperflorens Roxb. (1832) 730; Voigt (1845) 155. — Silvaea hookeriana Baill. (1858a) 342, nom. superfl. — Trigonostemon hookerianus (Baill.) Müll.Arg. (1866) 1109,nom. superfl. — Lectotype (designated by Yu et al. 2019): Roxburgh’s Flora Indica draw- ing, no. 2401 (CAL).

Small trees, 1–2.5 m tall; flowering branches 2.2–4.4 mm diam, pubescent when young, glabrous in older parts. Outer bark 0.1– 0.2 mm thick, pale brown; inner bark 0.1–0.2 mm thick, dark red; wood pale yellow, pith hollow. Stipules subulate, 0.7–2.5 mm long, caducous. Leaves: petiole terete but often furrowed above, 2.5–9 mm long, 1.5–2.7 mm diam, pubescent; blade oblan- ceolate, cuneately narrowed in lower part, 8–32 by 2.8–5.9 cm, chartaceous, base abruptly rounded to truncate, adaxial glands not seen, margin distantly serrate, teeth falcate when young, glandular or nipple-like when mature, apex acuminate to caudate, both surfaces glabrous; venation pinnate, midrib elevated and slightly pubescent on both sides, secondary veins 12–18 pairs, tertiary veins reticulate. Inflorescences unisexual or bisexual, rami- and cauliflorous, in short cymes or thyrses, or a single to a few flowers on short brachyblasts; peduncle 1.5–11 mm long, 0.5–0.9 mm diam, pubescent; bracts oblong to lanceolate, 0.3–5.6 by 0.2–1 mm, pubescent. Staminate flowers 3.8–4.9 mm diam; pedicel 2.2–2.5 mm long, 0.2–0.3 mm thick, glabrous; sepals elliptic, often unequal, 1–1.8 by 0.8–1.3 mm, base connate, margin entire, sometimes slightly ciliate, apex acute to rounded, pubescent outside; petals obo- vate to elliptic, 1.8–2.8 by 1.1–1.8 mm, base claw-like, apex rounded, glabrous, purple; disc lobes trapezoid, 0.2–0.3 by 0.2–0.25 mm, recurved at apex, glabrous; stamens 3, andro- phore 0.5–0.6 mm long, c. 0.1 mm diam; anthers free, divaricate at apex, thecae 0.4–0.5 mm long, connective with numerous droplets with secretion. Pistillate flowers (fruiting) 4.2–5.3 mm diam; pedicel c. 1 mm long, c. 0.5 mm diam when flowering, elongating in fruit to 2.5–4 mm long, 1.2–1.4 mm diam, glabrous to slightly pubescent; sepals elliptic to lanceolate, 1.1–2.5 by 0.65–1.2 mm when flowering, slightly accrescent to c. 5 by 2.1 mm when fruiting, base connate, margin entire or with 2 apical teeth, apex acute, pubescent outside; petals elliptic, c. 3.2 by 1.7 mm, base claw-like, apex rounded; disc not seen; ovary 1.5–1.8 mm diam, densely pubescent, stigmas 0.4–0.5 mm long, apically deeply bifid. Fruits: sepals persistent; columella 4–6 mm long. S eeds not seen .

Distribution — NE India, Bangladesh.

Habitat & Ecology — In forests. Elevation: 670–1000 m. Flowering: May.

Note — See note under T. flavidus .

Figures

Map 7 Distribution of Trigonostemon flavidus Gagnep. (X) and T. semperflorens (Roxb.) Müll.Arg. (▲).