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146 The Journal of the Royal Institute of Thailand Volume III - 2011 146 Taxonomic Revision of the Genus Hedychium J. Ko.. nig (Zingiberaceae) in Thailand (Part I) round, glabrous. Leaves subsessile, or shortly petiolate 1.2-1.5 cm long; blades elliptic, 25.6-32.5 by 12.5-17.7 cm, base cuneate, apex acute-acuminate, upper surface glabrous, lower surface hairy along the midrib . Inflorescence a terminal spike 12.0-20.5 cm long, peduncle 4.2-5.4 cm long; bracts imbricate, ovate to oblong, 6.4-7.0 by 2.8-3.8 cm, apex acute or obtuse, glabrous, each subtending a cincinnus of 1-2 flowers; first bracteole tubular, 5.5-5.9 by 0.5-0.6 cm, apex acute, glabrous, ribbed; second bracteole 4.9-5.4 by ca. 0.5 cm. Flower white to yellow, fragrant; calyx tubular, 8.2-8.8 cm long, apex acute, split on one side, glabrous except ciliate apex; corolla tubular, 13.4-13.8 cm long, glabrous, lobes linear, 6.0-6.2 by 0.2-0.3 cm, apex hooded; staminodes lanceolate, 6.2-6.6 by 1.4-1.6 cm, base attenuate into 1.5-2.1 claw, apex acute; labellum broadly obovate, 5.2-5.4 by 4.1-4.2 cm, base attenuate into 0.5-0.9 cm claw, apex deeply divided, cleft to a depth of 2.5-2.6 cm, apex of the lobes shortly acuminate; filament 5.3-5.4 cm long, yellow, anther dorsifixed, 1.4-1.5 cm long, base divaricate, yellowish; ovary glabrous, 4-7 by ca. 3 mm, 3-loculed, placentation axile; epigynous glands 2, slender, 1-2 by ca. 1 mm yellowish; stigma green, densely ciliate. Fruit oblong, 3.2-3.6 by 1.3-1.4 cm, red, crowned with persistent calyx. Thailand.›PENINSULAR: Nakhon Si Thammarat [Yong Waterfall National Park, Khao Maen; Khao Luang National Park, Lan Trai; Khao Nun National Park]. Distribution.›Endemic to Thailand. Ecology.›Lower montane rain forest, at the altitude of 1,093-1,237 m. Phenology.›Flowering July-August, fruiting August-September. Vernacular name.›Hong Hoen (Àß å ‡À‘ π). Note.›Three species of Hedychium in Thailand , H. cylindricum var. siamense , H. khaomaenense and H. malayanum possess cylindrical inflorescences. This taxon is, however, can be readily distinguished by its broadly obovate labellum, with deeply divided apex, each lobe with short acuminate apex. 9. Hedychium longicornutum Griff. ex Baker, in Hook.f., Fl. Br. Ind. 6: 228. 1894 [Type: Peninsular Malaysia: Malacca; Griffith ]; Ridl. J. Straits Brch. R. Asiat. Soc. 32: 100. 1899; K. Schum. in Engl., Pflanzenr. 4(46): 55. 1904; Ridl. Fl. Mal. Pen. 4: 242. 1924; Holtt. In Gard. Bull. Sing. 13: 77-78. 1950.› H. crassifolium Baker, in Hook.f., Fl. Br. Ind. 6: 228. 1894.› H. longicornutum var. minor Ridl., Bull. Misc. Inform. Kew. 1926: 88. 1926 [Type: Indonesia: Sumatra, Siberut, 28 September 1924; C. Boden-Kloss 14599 (K)]. 126-149_mac9 4/26/12, 9:15 PM 146