Tuesday, January 31, 2012

[Botany • 2011] Lecanorchis betongensis • A new species of Lecanorchis (Orchidaceae) from Thailand

Lecanorchis betongensis Suddee & H. A. Pedersen

Lecanorchis betongensis, a new species from tropical rain forest in southern peninsular Thailand, is described and illustrated. The combination of semicircular column wings and a labellum with an odd number of major veins (but devoid of calli) places the new species in sect. Lecanorchis. However, the lack of any fusion between the labellum and the column readily distinguishes L. betongensis from all other species of the genus. The new species seems morphologically closest to L. malaccensis from Thailand, Malaysia and Sumatra.

Key words: Flora of Thailand, Lecanorchis betongensis, orchids, systematics, taxonomy, Vanilloideae.

Fig. 2. Lecanorchis betongensis Suddee & H. A. Pedersen.
A: Underground organs. B: Habit. C: Flower. D: Flower (sepals and petals removed) A–D: Wai 2003.
 Photographed by T. Phutthai (A) and J. Sae Wai (B–D).

Etymology: The new species is named after the Betong District.

Distribution: Lecanorchis betongensis is apparently endemic to Thailand, but it might be expected also to occur across the border in Peninsular Malaysia.

Conservation: Known only from 4 collections from the type locality and a nearby locality within the same Subdistrict. The area is in Bang Lang National Park; it is well protected, but its flora is still poorly

Ecology: Mycoheterotrophic, apparently restricted to tropical rain forest at 500-700 m alt. Flowering:

Notes: The new species seems morphologically closest to L. malaccensis from Thailand, Malaysia and Sumatra. However, it differs from the latter species in having larger sepals and petals, and in its labellum being completely free from the column. Indeed, the lack of any fusion between the labellum and the column readily distinguishes L. betongensis from all other species of the genus. The combination of semicircular column wings and a labellum with an odd number of major veins (but devoid of calli) places the new species in sect. Lecanorchis as morphologically defined by Hashimoto (1990). However, the entire or only obscurely 3-lobed condition of the labellum in L. betongensis is not typical of sect. Lecanorchis.

Suddee, S. and Pedersen, H.Æ. 2011. A new species of Lecanorchis (Orchidaceae) from Thailand. Taiwania, 56(1): 37-41. http://tai2.ntu.edu.tw/taiwania/pdf/tai.2011.56.1.37.pdf