Trigonostemon victoriae R.Y.Yu & Welzen

5. Trigonostemon victoriae R.Y.Yu & Welzen View in CoL — sect. Trigonostemon — Fig. 6 View Fig ; Map 1 View Map 1

Trigonostemon victoriae R.Y. Yu & Welzen (2018) View in CoL 215, f. 15. — Type: PNH (Sulit) 12317 (holo L; iso PNH), Philippines, Palawan Province, Victoria Mts, Panacan, Aborlan .

Small trees,up to 6 m tall, dbh c. 10 cm;flowering branches (1.5–) 2–3 mm diam, pubescent near apical buds and glabrescent in mature parts. Outer bark 0.1–0.2 mm thick, brown when young, pale greyish in old parts, somewhat shiny; inner bark 0.1–0.2 mm thick, dark red, sap red; wood pale yellowish. Stipules subulate, 0.5–1 mm long, caducous, base pubescent, apex often glabrous. Leaves: petiole terete but grooved above, 1–13.5 cm long, 0.8–1.4 mm diam, pubescent when young; blade elliptic to oblong, 8.5–20.5 by 2.5–5.5 cm, chartaceous to coriaceous, base acute, 2 pairs of adaxial glands present, often pubescent, inner pair often smaller, margin distantly serrate, teeth glandular, apex acuminate to slightly caudate, upper side glabrous, green, lower side sparsely pubescent, pale green; venation penninerved, often pubescent on the lower side, midrib more or less raised above and elevated beneath, nerves 5–8 pairs, curved and narrowed along margin, veinlets reticulate. Inflorescences unisexual, often terminal or subterminal, involucral bracts as stipules; staminate flowers partly single and cauliflorous, others in racemes, rachis 1–5 cm long, 0.5–0.6 mm diam, appressed pubescent, flowers often only in upper half, bracts lanceolate to triangular, 1–3 by 0.3–0.6 mm, appressed pubescent; pistillate inflorescences often with only 1 flower at the top of inflorescences and sometimes a few abortive buds below; peduncles 1–5 cm long, 0.5–1 mm diam, pubescent; bracts lanceolate to elliptic, 1–4 by 0.3–0.7 mm, pu- bescent. Staminate flowers 3.7–4.6 mm diam; pedicel 0.5–1.5 mm long, 0.35–0.5 mm diam, pubescent; sepals triangular when young, ovate to elliptic when mature, 1–1.5 by 0.8–1.4 mm, green, imbricate, margin entire, apex acute to acuminate, pubescent outside; petals elliptic, 2.8–3 by 2.3–2.5 mm, dark red, base cuneate, margin entire, apex rounded, glabrous on both sides; disc lobes rhomboid, 0.2–0.25 by 0.3–0.4 mm, c. 0.1 mm thick, fleshy, apex acute; stamens 3, androphore c. 0.7 mm long, anthers ellipsoid, 0.6–0.7 mm long. Pistillate flowers 3–4.5 mm diam; pedicel 1.5–3 mm long, 0.4–0.7 mm diam, green, slightly sericeous; sepals lanceolate, 1.6–4 by 0.6–1.6 mm when flowering, accrescent to 10–13 by 2.5–4.5 mm when fruiting, green, margin with a few indistinct teeth, apex acute to acuminate, sericeous on both sides, denser outside; petals elliptic to ovate, 1.1–1.4 by 1–1.2 mm, glabrous except for ciliate margin; disc lobes rectangular, 0.15–0.2 by 0.2–0.25 mm, apex truncate, glabrous; ovary c. 0.65 mm diam, glabrous; style c. 0.1 mm long, stigmas deeply divided and reniform, arms straight, c. 0.3 mm long. Fruits c. 1.1 cm diam, sericeous, green; pedicel 1.05–1.25 cm long, thickening towards apex, 1.7–2.2 mm diam (apex), pubescent; sepals persistent, oblong, 9.5–11.2 by 3–4 mm, pubescent on both sides; columella c. 4.6 mm long. Seeds unseen.

Distribution — Philippines (Victoria Mountains, endemic).

Habitat & Ecology — Dipterocarp forests, growing on clay, near rivers.Altitude: 78–195 m. Flowering: March to May; fruit- ing: March to April.

Note — The species is found at the foot of the Victoria Moun- tains. The petiole can be as long as 13.5 cm, which is similar to T. longipes . New descriptions of inflorescences, mature staminate and pistillate flowers and fruits are presented. One of the striking characters of the species is the enlarged sepals in the pistillate flowers. The species is seen to cohabit with ants ( Fig. 6d, f–h View Fig ; RYY pers. obs.).

6. Trigonostemon villosus Hook.f. var. merrillianus (Airy Shaw) R.Y.Yu & Welzen — sect. Trigonostemon — Fig. 7 View Fig ; Map 3 View Map 3

Trigonostemon villosus Hook.f.var. merrillianus (Airy Shaw) R.Y. Yu & Welzen (2018) View in CoL 218. — Trigonostemon merrillianus Airy Shaw (1971) View in CoL 549; (1975) 203. — Dimorphocalyx View in CoL (?) borneensis Merr. (1916a) 73. — Lectotype (designated here): Hose 420 (L; iso K), Sarawak, 4th Division, Baram District, Entoyut River.

Trigonostemon acuminatus Merr. (1916b) View in CoL 190; Pax & K.Hoffm. (1919) 41; Merr. (1923) 451; Airy Shaw (1983) 46. — Type: BS (Ramos) 24528 (BM, BO, K, L), Philippines, Samar, Catubig River .

Trigonostemon laxiflorus Merr. (1920) 567;(1923) 451; Airy Shaw (1983) 47. — Type: BS (Ramos & Edaño) 31097 (A*, K, P, US), Philippines, Panay, Capiz Privince, Jamindan.

Small trees, 1–4 m tall, dbh up to 6 cm; flowering branches 2.5–4.5 mm diam, often pubescent when young, glabrescent when mature, buds pubescent. Outer bark 0.1–0.2 mm thick, dark brown, sometimes fissured; inner bark 0.1–0.2 mm thick, dark greenish or reddish, sap watery, translucent; wood white. Stipules subulate, 0.5–1.9 mm long, base pubescent. Leaves : petiole terete but often furrowed above, 1–11 cm long, glabrous to hirsute, sometimes slightly thickened at base and apex, 1.2–2.1 (middle)– 3.5 mm (base and apex) diam; blade oblong, 8–29 by 2.2–9 cm, chartaceous, base acute to rounded, 2 adaxial glands present, margin distantly serrate, teeth subulate or glandular, apex acuminate to caudate, upper side glabrous, dark green, lower side paler green, slightly pubescent, particularly on venation; midrib flat or slightly raised above and distinctly elevated beneath, nerves 8–13 pairs, often bow-shaped, con- nected along margin, veins reticulate, sometimes obscure. Inflorescences unisexual, often axillary, staminate flowers partly single and cauliflorous, others clustered in cymes or glomerules, rachis 10–18 cm long, 0.8–1 mm diam, bracts linear to lanceo- late, 0.5–10.5 (Palawan)–18 (Samar) by 0.3–3.3 (Palawan) –6.5 (Samar) mm, margin entire, pubescent; pistillate ones racemose, often only 1–3 flowers present at top, rachis 5.5–22 cm long, 0.4 ( Mindanao ) –0.6–1.3 (Samar and Palawan) mm diam, pubescent, bracts lanceolate, 4.2–11 ( Mindanao and Palawan)–19 (Samar) by 0.4 ( Mindanao )–2.5–7.3 (Samar and Palawan) mm, margin distantly serrate, teeth glandular, pubescent outside. Staminate flowers 5–6.7 mm diam, pedicel 1.3–3 (Palawan)–4.5 (Samar) mm long, 0.2–0.5 mm diam, light green, glabrous; sepals elliptic, 1.2–2 by 0.6–1 mm, im- bricate, white, margin ciliate, apex rounded, slightly pubescent outside; petals elliptic, 2.4–3.8 by 1.2–2 mm, purplish black, with a flame-like honey mark in the centre (Palawan), margin entire, apex rounded, glabrous on both sides; disc lobes rectangular or obtrapezoid, 0.25 (Samar)–0.4–0.5 (Palawan) by 0.2 (Samar)–0.45–0.6 (Palawan) mm, yellowish, apex truncate or rounded; stamens 3, androphore 0.5–0.9 mm long, anthers ellipsoid, 0.65 (Samar)–0.9–1.1 (Palawan) mm long, pinkish red, connective apically with numerous reddish droplets with secretion. Pistillate flowers 6–8 mm diam, pedicel often slightly thickened towards apex, 5–6 (Palawan)–10.5 (Samar) mm long, apically 0.5–1.5 mm diam, green, appressed pubescent; sepals lanceolate to elliptic, 2–2.4 (Samar)–6.5 (Palawan) by 0.8–2 mm when flowering, sometimes accrescent when fruit- ing (Palawan), green or red when flowering, red when fruiting, margin serrate, apex acuminate, appressed pubescent outside, sometimes with an apical gland (Palawan); petals as staminate flowers but longer and caducous, 3–3.6 by 1–1.2 mm; disc lobes rectangular, 0.3–0.9 by 0.5–0.6 mm, membranous, apex rounded or truncate; ovary 1–1.1 mm diam, densely villose, style short, indistinct, stigmas 3, completely bifid, free arm 0.8–1.3 mm long. Fruits c. 0.9–1.2 cm diam, villose; pedicel c. 1.5 cm long, thickening towards apex, c. 1.4 mm diam (apex); sepals persistent, red; wall 0.4–0.5 mm thick; columella 4–6 mm long. Seeds globose, c. 5 mm diam, marbled .

Distribution — Borneo and Philippines (new record for Pala- wan).

Habitat & Ecology — In the Philippines, growing in the understorey of dipterocarp forests, on red clay loam soil, along the coast. Altitude: 10–40 m. Flowering: March to April (Samar and Palawan); May to June ( Mindanao ); fruiting: February to March (Samar) .

Note — The description is only based on collections from the Philippines. Trigonostemon villosus var. merrillianus is an extremely variable taxon, but in the Philippines it is less variable in the length of the petiole and the size of the leaf blade. Taxa that are easy to confuse with T. villosus var. merrillianus are T. villosus var. borneensis (differs from the former by the shorter petiole and non-accrescent sepals in the pistillate flowers), T. oblongifolius (differs by flabellate petals with a claw-like base and lacking a honey mark), T. polyanthus (differs by the paintbrush-like instead of glomerate staminate inflorescences) and T. filiformis (differs by the narrower leaf blade, slender inflorescences and non-accrescent sepals in pistillate flowers).