Laosanthus K. Larsen & Jenjitt.
Nordic J. Bot. 21(2): 135 (2001)
Type: L. graminifolius K. Larsen & T. Jenjitt. sp. nov.
Delicate, perennial herb, 50-60 cm high, with inflorescence up to c. 1 m. Rhizome horizontal, short, ovoid, c. 1 cm long. Basal leaf sheaaths without lamina, 2-3. Leaves 2-3, lamina sessile, linear, 15-29 by 1.5-1.1 cm, tapering towards the 15-19 cm long sheath, strongly keeled almost to apex, the inner leaves longer and narrower than the outer, base narrowly cuneate, apex acuminate; libule very short, less than 1 mm, often as a mere line across sthe leaf. Inflorescence apparently terminal on the leafy shoot; peduncle 50-90 cm, glabrous, slender, elliptic in cross section, 3-4 mm diam. Floral axis 3.5-8 cm long, similar to the peduncle but slightly thinner. Bracts green, oblong, glabrous, 5-10, 1-1.5 by 1.2-1.7 mm, spirally arranged, spaced, not joined, leaving the rachis visible, apex truncate to broadly mucronate, curled back; each bract subtending a cincinnus with 4-7 flowers. Axis terminated by a coma of 6-9 free, sterile bracts, pinkish to purple, narrowly oblong, apex rounded to shrotly acute, 3-5 by 1-1.5 cm. Bracteoles transparent, triangular, c. 5 by 5 mm. calyx tubular, 4.5-6.5 mm long, split 1.5-2 mm down one side, apex 3-dentate, teeth rounded, 1-2 mm. corolla tube 5-10 mm long, narrowly funnel-shaped; corolla lobes 7-10 by 3.5 mm, dorsal lobe oblong, acute to rounded, hooded; lateral lobes similar but slightly shorter. Labellum yellow, triangular to circular in outline, 8-12 by 9 mm, bilobed, 3-5 mm deep to almost entire, lobes acute to rounded. Filament 1.5 by 1-2.2 mm; pollen sacs oblong, 4 by 2 mm, oopening by longitudinal slits; anther crest quadrangular to semicircular, emarginate, c. 2 mm. Ovary globuse to ellipsoid, 2 by 1.5 mm, 3-locular with central placentation, glabrous. Style glabrous; stigma obliquely funnel-shaped, frontside truncate, irregularly serrulate, backside obtuse, shallowly emarginate. Capsule subglobose to depressed globose, 8-11 by 0.7-10 mm diam., pale yellowish. Seeds subglobose, 3-3.5 mm, pale brown. Aril white, lacerate. (From Larsen and Jenjittikul, Nordic Journal of Botany 21(2) 2001)
Collected in Laos (and may be found in other parts of SE Asia?)
Comprises thus far only one species, L. graminifolius.
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