Volume 12 > Part 1 > Year 2011 > Page 275 > Orchidaceae > Vanilla

5. Vanilla siamensis Rolfe ex Downie

Bull. Mise. Inform. Kew 1925: 410. 1925; Gagnep., Fl. Indo-Chine 6: 584. 1934; Seidenf. & Smitinand, Orchids Thail.: 60, 728, fig. 41. 1959–1965; Seidenf., Dansk Bot. Ark. 32(2): 138. fig. 86. 1978; S.C.Chen & P.J.Cribb in Z.Y. Wu et al. (eds), Fl. China 25: 167. 2009. Fig. 161: Plate XXIII: 3.

Accepted Name : This is currently accepted.

Description : Stems climbing up to several meters high, cylindric, green, 5–10 mm in diameter, longitudinally grooved; aerial roots thin to thick, each of them perpendicular to a petiole. Foliage leaves elliptic, 15–25 by 5.5–11.5 cm, apex acuminate, coriaceous, glabrous; petiole 1–2.2 cm long. Inflorescence 5- to 18-flowered; rachis 6–10 cm long, glabrous; bracts ovate, 7–8 by 4–5 mm, persistent, coriaceous, glabrous. Flowers showy, long-pedicelled, opening widely at first, afterwards closed. Sepals glabrous, greenish-yellow, oblanceolate, apex acute, slightly hooded; dorsal sepal 3.8–5 by 1.2–1.6 cm, 17- to 19-veined; lateral sepals 3.7–5 by 1.2–1.7 cm, 13- to 17-veined. Petals glabrous, greenish-yellow, oblanceolate, 4–4.7 by 1.3–2 cm, 15- to 19-veined, with strong midvein outside, apex acute, not hooded. Labellum white, with purple throat, ovate in outline, obscurely 3-lobed, 3.5–4.5 cm long along the mid-line, with a brush on disc opposite anther, 3–5 mm high, consisting of close transversal flat hinged scales, dented or fringed along the truncate apex, pointing downwards in the flower; side lobes rounded, overlapping and enclosing the column, adnate to the column up to below stigma, the apical margins wavy, 3–3.5 cm across both sides when spread out; midlobe ovate, 1.5–2 cm wide at base, 1–1.5 cm long, margin wavy, with fat papillae near apex, papillae 5–8 mm long. Column slender, 2.2–2.5 cm long, villous on front, slightly winged at the top; anther ca 2 mm long, glabrous. Ovary (including pedicel) 2–3.5 cm long. Berry oblong, 15–22 by 1–1.5 cm.

Thailand : NORTHERN: Chiang Mai (Doi Suthep – type: Kerr 095, holotype -K, isotype -TCD), Chiang Rai, Lampang, Nan; SOUTH-WESTERN: Kanchanaburi; SOUTH-EASTERN: Chanthaburi.

Distribution : S China (S Yunnan).

Ecology : In hill evergreen forests and tropical evergreen forests; 200–1,200 m alt. Flowering: April–August.

Vernacular : Phlu chang (พลูช้าง)(Chiang Mai); tong pha (ตองผา)(Shan-Northern).