Siamanthus K. Larsen & J. Mood
Nordic J. Bot. 18(4): 393 (1998).
Type: S. siliquosus K. Larsen & J. Mood
Rhizomatous herb up to 150 cm, forming compact clumps. Rhizome 1.5-2 cm, fibrous, outside light green, inside tan with a darker central core, new rhizomes raised above the soil on stout aerial roots. Leaves transverse to the rhizome. Pseudostem in cross section oval, 1 by 1.5 cm at base, tapering towards apex, faintly striate, puberulous, waxy, light green. Base covered by c. 3 sheaths, followed by c. 9 leaves increasing in size upwards. Ligule 12-15 mm, white, translucent, entire, rounded to almost truncate, puberulous with longer, white hairs along the margin. Petiole 4 by 15 mm, puberulous. Lamina 7-8.5 by 44-59 cm, vary narrrowly elliptic, base attenuate, apex acuminate, margin with long, curved hairs pointing towards apex; upper surface glabrous, green, midrib sunken with 5-12 unevenly spaced nectary pits, secondary veins raised; lower surface sericeous, light green. Inflorescence lax with 8-12 flowers. Axis dark red, glabrous, slender, 20-25 cm long. Flowers single, ebracteate, resupinate, 1-3 cm, provided with a rudmentary bractelole in the form of cushion less than 1 mm, situated about the middle of the pedicel or above. Ovary trilocular, 5-10 mm, with numerous ovules. Stylocial glands 2, 8-10 mm, rather thick. Calyx red, tubular, 3-4 cm, bidentate with teeth 5-7 mm long, split down 1/4-1/3 one side. Corolla tube orange-red, 5-6 cm long, much widenened to almost saccate above the calyx mouth. Dorsal corolla lobe orange, c. 9 mm long, 8-9mm broad, narrowed towards the acute apex forming an "upper lip", during anthesis turned upwards. The proximal 2-3 cm of "lower lip" forms a groove with raised margins, orange red in the middle, dark purple along the margins; distal part red, conisting of 3 filiform lobes, the middle one c. 4 cm, the lateral ones c. 7 mm. Filament orange, 8-20 mm oopening by longitudinal slits. Style placed in a furrow in the stamen appearing on top of the anther, later during the anthesis free from the anther; stigma green, obliquely funnel-shaped with smooth margin. Capsules 5-11 by 0.5 cm, droooping on a 1-3.5 cm long stalk, crowned by rudiments of calyx and stylodia, opening by 3 longitudinal slits, exposing the seeds on the central, filiform placenta. Seeds angular, c. 2 by 1.5 mm, with a white, bifid arillus. (From Larsen & Mood, Nordic J. Bot. 18(4): 393 (1998))
Endemic to the Naratahiwat province of S Thailand.
Only one species, S. siliquosus K. Larsen & J. Mood.
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