e-Flora of Thailand

Volume 12 > Part 1 > Year 2011 > Page 292 > Orchidaceae > Zeuxine

6. Zeuxine membranacea Lindl.

Gen. Sp. Orchid. Pl.: 486. 1840; N.Pearce & P.J.Cribb, Fl. Bhutan 3(3): 113. 2002; S.C.Chen et al. in Z.Y. Wu et al. (eds), Fl. China 25: 72. 2009. Fig. 170.


Accepted Name : This is currently accepted.



Synonyms & Citations :

Tripleura pallida Lindl., Gen. Sp. Orchid. Pl.: 452. 1840.
Zeuxine tripleura Lindl., J. Proc. Linn. Soc., Bot. 1: 186. 1857, nom. illeg.
Zeuxine strateumatica auct. non (L.) Schltr.: Seidenf. & Smitinand, Orchids Thail.: 84 p.p., fig. 64. 1959; Seidenf., Dansk Bot. Ark. 32(2): 79 p.p., fig. 48. 1978; Seidenf. & J.J.Wood, Orchids Penins. Malays. Singap.: 85 p.p., fig. 32a–g. 1992.


Description : Flowering shoots (15.5–)22–48 cm tall. Foliage leaves sessile, narrowly linear-lanceolate, acute to acuminate, 1.7–6.7 by 0.2–0.5 cm. Inflorescence pubescent; rachis 2–9 cm long; bracts (linear-)lanceolate, (sub)acuminate, pubescent on the dorsal side, 4–10 by 1.7–3 mm. Flowers (sub)sessile, white. Sepals 1-veined, pubescent on the dorsal side; dorsal sepal ovate, obtuse, 3.3–4.1 by 2.8–3.1 mm; lateral sepals obliquely lanceolate-oblong, obtuse to subacute, 3.1–3.2 by 1.5–1.6 mm. Petals adherent to the dorsal sepal, obliquely (oblong-)oblanceolate, not abruptly narrowed below the apex, 3.7–4.2 by 1.2–1.6 mm. Labellum 3–3.2 mm long along the mid-line; hypochile inside with 1 papilla-like appendage on either side; mesochile smooth (or nearly so) on the outside; epichile bilobed, truncate when spread out, wider than the hypochile, lobules semicircular to semielliptic, 1.1–1.3 by ca 1.2 mm (length measured along the hind edge), 0.9–1.1 time as long as wide. Column devoid of ornaments on the front. Ovary densely pubescent. Capsule (sub)erect, subsessile, ellipsoid, pubescent, 0.3–0.5 cm long, 0.2–0.3 cm in diameter.


Thailand : NORTHERN: Chiang Mai; EASTERN: Ubon Ratchathani (Bung); SOUTH-EASTERN: Sa Kaeo, Prachin Buri; PENINSULAR: Songkhla (Padang Besa).


Distribution : Distribution insufficiently known, but includes at least India, Bhutan (type), Bangladesh, Myanmar, Laos, Cambodia, Vietnam, Hong Kong and Papua New Guinea.


Ecology : Savanna forests and open deciduous forests; 50–1,100 m alt. Flowering: recorded in December–January, March and August.


Notes: Hooker (1890–1894) included Zeuxine membranacea in the synonymy of Z. sulcata (Roxb.) Lindl., and Seidenfaden (1978) followed Garay & Sweet (1974) in treating both names as synonyms of Z. strateumatica (L.) Schltr. However, I agree with Pearce & Cribb (2002) that Z. membranacea and Z. strateumatica are two clearly distinct species that are mutually distinguished by a number of morphological features.

In Zeuxine membranacea, a number of unusual appendages are often found on the column (fig. 170). They have the texture, shape and size of massulae from pollinia of the fertile median anther, but they are found in connection with the vestigial lateral anthers. According to Jaap J. Vermeulen (in litt.), the vestigial anthers in such cases probably develop a few fully grown massulae - rendering the flowers in question partially peloric.


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