Saturday, June 25, 2011

[Botany • 2009] ซายเหินป่า, ตาเหินจัมปาศักดิ์ | Hedychium champasakense Picheans. & Wongsuwan • from Southern Laos

ซายเหินป่า, ตาเหินจัมปาศักดิ์
| Hedychium champasakense Picheans. & Wongsuwan
from Southern Laos

Hedychium champasakense (Zingiberaceae) from Southern Laos

Chayan Picheansoonthon and Pornpimon Wongsuwan

Abstract: A new species, Hedychium champasakense (Zingiberaceae), from Southern Laos is described and illustrated. It canbe easily differentiated from its closest taxon, H. speciosum Wall., by its elliptic leaves, longer ligules with shallowly bilobe apices,the calyx tubes being shorter than the bract, the lanceolate-oblong or spathulate staminodes with the acute to rounded apices, and thesub-orbicular to orbicular labella with the 2-clefted apeces and the short claws. The relationship with other related species is alsodiscussed.

KEY WORDS: New species, Hedychium champasakense, Zingiberaceae, Southern Laos

Type: Picheansoonthon 859, Laos PDR, ChampasakProvince, Dan Nong Luang, the Bolaven Plateau, N 15°04.330’, E 106° 42.152’, alt 920 m, 15 June 2005(holotype BKK, isotype BK, SING).

Distribution: This new species is only known from thetype location on the Bolaven Plateau of Champasak Province in Southern Laos.Ecology: This new species grows along the edge of thelower montane scrub and in the open areas of the gapwetland (blanket marsh) vegetation, at the altitude of930-970 m.

Vernacular names: Sai-hoen, Wan Sai-hoen,Sai-hoen Pa.

Use: Medicinal.

Fig. Hedychium champasakense Picheans. & Wongsuwan. A: The flowering plants in the type location. B: Part of theleaves and ligules. C: Young inflorescence, showing bracts. D: An inflorescence. E: Details of the flowers. F: Aninfructescence, showing a mature fruit and a dehiscing fruit. (photographed by Chayan Picheansoonthon)

Note: This new species belongs to the group of Hedychium with long anther and emarginated toshallowly-clefted labellum. Based on specimens investigated, it is closest to Hedychium speciosum Wall. but can be easily differentiated by its elliptic leaves,longer ligules (2.7-3.1 cm versus ca. 2 cm) with shallowly bilobed apices, calyx tube being shorter thanthe bract, lanceolate-oblong or spathulate staminodes with the acute to rounded apices, and sub-orbicular toorbicular labellum with the 2-clefted apex and the shorter claw (6-7 mm versus ca. 1.5 cm).

It is also somewhat morphologically resembled H. gardnerianum Sheppard ex Ker. Gawl. and H. ellipticum Buch.-Ham. ex Sm. However, the prior taxon can bereadily distinguished by its oblong leaf blades, 4-5-flowered bracts and hairy calyx tubes. The latter species can be easily identified by its petiolated and glabrous (both surfaces) leaves, shorter glabrous ligules, 1-flowered bracts, oblanceolate labellum, and glabrous ovaries.

From our intensive fieldwork in southern Laos during the past few years, we can only found a small population of H. champasakense in a very smallrestricted area of the type location. Its type locality isonly few meters from the type locations of two other endemic taxa of the family Zingiberaceae, H.chayanianum Wongsuwan (Wongsuwan, 2008) and Jirawongsea burttii (K. Larsen & Jenjitt.) Picheans. (Picheansoonthon et al., 2008). However, H. chayanianum Wongsuwan can be seen in few other localities of the Bolaven Plateau.

Picheansoonthon, C., and Wongsuwan, P. 2009. Hedychium champasakense (Zingiberaceae) from Southern Laos. Taiwania, 54(2): 145-148.: