Tetrastigma macrocorymbum Gagnep. ex J.Wen, Boggan & Turland

Kochaiphat, Phongsakorn, Trias-Blasi, Anna & Pornpongrungrueng, Pimwadee, 2014, A new combination and new records of Tetrastigma (Vitaceae) from Thailand, Phytotaxa 183 (4), pp. 272-278 : 276-277

Tetrastigma macrocorymbum Gagnep. ex J.Wen, Boggan & Turland in Hui & Wen (2007: 205).

Type:— Vietnam, Tonkin, Moc-chau, prov. De Sonla, Petelot 7826 (holotype P). ( Fig. 1B )

Large woody climber. Stems pubescent with brownish hairs, slightly striate, mature stems flaky, flatted; tendrils simple; stipules 2, caducous. Leaves compound, pedately 5-foliolate; petiole 5.5–7.0 cm long, pilose, base pulvinate; leaflets papyraceous; terminal leaflet petiolule, 1–2 cm long, pilose, terminal leaflet blade elliptic or ovate, 11.5–15.5 × 5–6 cm, base attenuate or cuneate, margin serrate with small 0.5–1 mm protruding, apex acuminate, petiolule of lateral leaflet complex 1–1.5 cm long, pilose, lateral leaflet petiolule, 0.5–0.7 cm long, pilose, lateral leaflet blade elliptic or ovate, 8–13 × 4–6 cm, base cuneate or asymmetrical, margin and apex as terminal leaflet; veins conspicuous on both sides, protruding on lower surface, pilose, 1 main basal vein, 8–11 pairs of lateral veins. Inflorescences in female plants axillary on young stems, compound umbel, globose, ca. 4 cm in diameter; peduncles 2–4 cm long, pilose, male plants not seen. Female flowers bud ovoid, 2–3 mm long, pedicels 2–3 mm long, pilose; calyx cupuliform, 4-tiny-lobed, pilose, margin ciliate; corolla squarrose at anthesis, petals oblong, 2.5–3 × 1.2–1.5 mm, apex with cornicules 0.2–0.3 mm long, outer surface puberulent; disc inconspicuous; staminode trullate, 1.5–2.0 mm long; ovary pyramiform, 1.5–2 × 2–2.3 mm, cover with hairs on the upper part; style ca. 0.5 mm long; stigma 4-lobed, 0.3–0.5 mm long. Berries not seen.

Distribution:— China, Vietnam and Thailand.

Distribution in Thailand:—NORTHERN: Chiang Mai ( Fig. 2 .).

Ecology:—Limestone mountains, in upper montane forest, at 1700 m elev.

Vernacular:—Thao Nam (เถาน้ำ) Chiang Mai.

Specimens examined:— THAILAND. Chiang Mai: Doi Chiang Dao, Dong noi, 1700 m elev., P . Kochaiphat 271 ♀ fl. ( KKU), 30 April 1997 , BGO. Staff. 9401 ♀ fl. ( QBG) .

Conservation status in Thailand:— A single population of this species has been recorded, and is represented by only two specimens. Because its habitat is very restricted and specific (upper montane forest on limestone soil at high elevation), a preliminary assessment of endangered ( EN) is indicated .

Note:—This species is similar to T. siamense Gagnep. & Craib in Craib (1915: 427) but differs in the presence of light-brownish hairs on the upper part of the ovary.

Tetrastigma pyriforme Gagnep. (1944: 35) . Syntype:— Vietnam, Tonkin, col de Lo-qui-ho, près Chapa , Polaine 12618 (not located), Sau-Tan-Nai, 8 April 1936, Poilaine 25626, ♂ fl. ( P!, BO!); Laos, Pakson , Bassac , Poilaine 15595 ( K!), Plateau des Bolaven, Poilaine 16196 (not located).

Sub-woody climber. Stems terete, mature stems flaky; tendrils bifurcate; stipules 2, deltoid, 0.3–0.4 × 0.4–0.5 cm, glabrous. Leaves compound, pedately 5-foliolate; petiole 6.5–9.0 cm long, pilose, base pulvinate; leaflets subcoriaceous; terminal leaflet petiolule, 1–1.5 cm long, pilose, terminal leaflet blade ovate–lanceolate, 3–4 × 6–9 cm, base acute, margin serrate with small robust-teeth at apex, apex cuneate, petiolule of lateral leaflet complex 0.6–0.8 cm long, pilose, lateral leaflet petiolule, 0.05–0.3 cm long, pilose, lateral leaflet blade ovate–lanceolate or unequally rhombic, 2.5–8 × 1.5–4.5 cm, base oblique, margin and apex as terminal leaflet; veins conspicuous on both sides, protruding on lower surface, pilose, 1 main basal vein, 7–17 pairs of lateral veins. Inflorescences in female plants axillary or on pseudo-terminal branch, cyme, male plants not seen. Flowers not seen. Berries pyriform when dry, 0.5–0.7 × 0.6–0.7 cm, 2–4 seeded. Seeds pyriform, triangular, apex retuse, ca. 0.5 × 0.6 cm, testa tuberculate, adaxial surface with a V-shaped furrow, abaxial surface with an elliptic chalaza, endosperm ‘ ’ shaped in cross-section.

Distribution:— Laos, Vietnam, Thailand and Malay Peninsula.

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

Ecology:—Shaded area in lower montane forest; 1700 m elev.

Phenology:—Fruiting in July.

Specimens examined:— THAILAND. Nan: Doi Phu Kha , 19̊ 25’ N , 101̊ 10’ E, 28 July 1992, K . Larsen, S. S. Larsen, C. Niyomdham, P. Sirirugsa , D.D. Tirvengadum & C. T. Norgaard 43683 ♀ fr. ( AAU, BKF) .

Conservation status in Thailand:— A single population of this species has been recorded, and is represented by only one specimen collected in Doi Phu Kha National Park (Nan) in 1992. This species has an extremely restricted distribution and it might be affected by deforestation, as there are anecdotal records of it in the area, therefore a preliminary assessment of endangered ( EN) is indicated .

Note:—This species is similar to T. serrulatum (Roxb.) Planch. (1887: 432) but differs from it in the number of secondary veins and stem morphology. While T. pyriforme has leaves with 7–17 pairs of secondary veins and a stout stem with flaky bark, T. serrulatum has leaves with 5–8 pairs of secondary veins and a slightly corrugated stem with a smooth surface.

Tetrastigma triphyllum (Gagnep.) W.T. Wang (1979: 83) . Tetrastigma yunnanense Gagnep. var. triphyllum Gagnep. in Lecomte (1910: 271). Type:— China, Yunnan, environs de Lou-lan, 16 March 1905, Ducloux 3439 ♀ fl. (holotype P!)

Figures

FIGURE 1. A. T. assimile, B. T. macrocorymbum, and C–D. T. triphyllum var. triphyllum. (A. photo by Phongsak Phonsena)

FIGURE 2. Distribution map of T. assimile (), T. macrocorymbum (), T. pyriforme (') and T. triphyllum var. triphyllum () in Thailand.