Tetrastigma yunnanense var. triphyllum

var. triphyllum View in CoL ( Fig. 1C, D View FIGURE 1 )

Sub-woody climber. Stems terete, mature stems flaky; tendrils palmately 5–7 branched; stipules 2, ovate-deltoid, 0.3–0.6 × 0.3–0.5 cm, glabrous. Leaves compound, palmately 3-foliolate; petiole 2.5–8.0 cm long, pilose; leaflets papyraceous; terminal leaflet petiolule 0.1–0.3 cm long, pilose, terminal leaflet blade rhombic-broadly lanceolate, 2.8– 9.0 × 1.0– 4.5 cm, base cuneate-obtuse, margin broadly serrate with teeth at apex, apex acute-attenuate, lateral leaflet petiolule, 0.05–0.2 cm long, pilose, lateral leaflet blade ovate-lanceolate, 1.5–6.5 × 0.8–3.8 cm, base asymmetricalround or asymmetrical-cuneate, margin as terminal leaflet, apex acute; veins conspicuous on both sides, 1 main basal vein, 5–8 pairs of lateral veins. Inflorescences in female plants on pseudo-terminal branch, compound umbel, globose, 2–2.5 cm in diameter; peduncles 1–1.2 cm long, pilose, male plants not seen. Male flowers not seen. Female flowers bud 0.2–0.25 cm long, pedicels 0.2–0.35 cm long, slightly pilose; calyx disciform, lobe-inconspicuous, glabrous, margin entire; corolla squarrose at anthesis, petals ovate, 0.2–0.3 × 0.1–0.2 cm, apex rounded, outer surface glabrous; disc membranaceous, adnate to the lower part of ovary; staminode filiform, 0.6–0.8 mm long; ovary ovoid, 1.8–2.0 × 1.7–2.0 mm; style truncate, ca. 0.5 mm long; stigma 4-lobed, callose. Berries and Seeds not seen.

Distribution:— China and Thailand.

Distribution in Thailand:—NORTHERN: Nan ( Fig. 2 View FIGURE 2 ).

Ecology:—Limestone mountains, in upper montane scrub forest, at 1750 m elev.

Phenology:—Flowering in February.

Specimens examined:— Thailand. Nan: Doi Phu Wae, P. Srisanga, S. Sasirat, W. Pongamornkul, S. Sukiam & P. Panyachan 2422 ♀ fl. ( QBG, Herbarium of Biology Department , Chiang Mai University) .

Conservation status in Thailand:— A single population of this species has been recorded, and is represented by only one specimen collected in Doi Phu Wae, Doi Phu Kha National Park ( Nan). This species has an extremely restricted distribution with a very specific habitat (upper montane scrub forest on limestone soil), therefore a preliminary assessment of endangered ( EN) is indicated .

Note:—This species is distinguished by its palmate tendrils and 3-foliolate leaves. It is the only species from Thailand with palmate tendrils. This variety differs from Yunnan ( China) endemic var. hirtum (Gagnep.) W.T. Wang (1979: 84) , by its densely pilose young branches, leaves, petioles and pedicels.