THAI FOREST BULLETIN (BOTANY) 36
veins simple or once forked, 19–23 pairs, intramarginal vein present, inconspicuous, veins anastomosing with included free veinlets. Inflorescences axillary or terminal; peduncle 5– 12 cm long, diameter 4–5 mm, thick, fleshy, pubescent; pseudoumbel convex, positively geotropic, of 1–19 flowers, lasting 2–3 weeks; bracts triangular, 1–3 by 2–5 mm, outer surface pubescent; pedicels uniform 6.5–7 cm long with scattered glands below the receptacle, pubescent. Calyx persistent, 5 lobed, 2–2.5 cm in diam., pale green, outer surface pubescent with scattered glands, inner surface glabrous; calyx lobes ovate, apex ± acute, based overlapping, quincuncial, 7–10 by 6–8 mm. Corolla spreading in star-shape when fully open, 5 lobed, 7–9 cm in diameter.; corolla tube shorter 1–1.5 cm long, inner surface creamy white, between lobes reddish-purple, finely pubescent, outer surface pale yellow to pale green with sparsely reddish-purple glands, glabrous; corolla lobes ovate, 2.5–3 by 2– 2.5 cm, apex acute, inner surface dark red or reddish-purple, outer surface pale yellow to pale green with scattered reddish purple glands, glabrous on both surfaces, margin recurved with ciliate hairs. Corona massive, diameter ca 2 cm, creamy white, outside glabrous, with very short pubescent stalk; coronal scales ovoid, ca 10 by 4.5 mm, inner angle ± acute, outer angle retuse, raised from corolla, ca 1.2 cm thick; inner lobe with a conical process or a spine like appendage, inside solid with dense soft spongy-like tissue around stigma; outer lobe blunt, upcurved, inside hollow, inner surface pubescent; anther appendage covering the receptive area of stigma, creamy white; anther wing rigid ca 0.35 cm long, yellowish-white; corpuscle brownish-black, small ca 0.5 mm, slightly rounded- subquadrangular; pollinia winged, obliquely oblong, 2–2.5 by 0.5–0.7 mm, yellow. Style head ± quadrangular, conical, 8–9 by ca 6 mm, creamy white. Ovaries 5–7 mm long, pale green, glabrous; style very short; ovules numerous. Fruits and seeds not seen.
Thailand.— PENINSULAR:Yala [Betong district, Gunung Silipid, 8 Jan. 2006, Wai 540 (PSU, BCU)]
Distribution.— Borneo and Peninsular Malaysia.
Ecology.— On thin layer moist podzolic soil over a rocky base, among metamorphic rock (Quartzitic phyllite) crevice of (one) mountain ridge; altitude 650 m; recorded from mangrove and lowland forest (outside Thailand). Very rare in Thailand. Flowering in December-February.
Note.— Only one plant was found in the present study. Additional specimens and field surveys along Thai-Malaysian border are still needed.
The first author would like to thank Mr. Nopadol Sae Wai for his kind support of the field work. This work was supported by the TRF/BIOTEC Special Program for Biodiversity Research and Training grant (BRT) T_149011 and the Graduate School, Prince of Songkla University.
Hooker, J.D. (1883).Asclepiadaceae. In Hooker, J.D. (ed.), Flora of British India 4: 52–63. L. Reeve & Co., London.