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120 Notes on the genus Hedychium J. Konig (Zingiberaceae) known for Thailand The Journal of the Royal Institute of Thailand Vol. 33 No. 3 Jul.-Sep. 2008 .. Roxb., and H. hirsutissimum Holtt. In the same year, two new species, H. khaomaenense Picheans. & Mokkamul and H. thaianum Mokkamul & Picheans., were added (Picheansoonthon and Mokkamul, 2006). Resulting from our herbarium specimen investigation and intensive field works on the genus Hedychium J. K nig in Thailand, taxonomic notes on the twenty-one species and four varieties currently enumerated for Thailand are given. Some key taxa are also illustrated. Description and illustrations of H. malayanum Ridl., a new record for Thailand, are given. Synops i s of the known Hedychium in Thailand 1. H. aureum C. B. Clarke & Mann ex Baker in Hook.f., Fl. Brit. Ind. [J. D. Hooker] vi, (1892) 299. Type: to be selected This species is a small plant with beautiful golden-yellow flowers found in evergreen forests of high altitude mountain ranges ( elevation 1,300-1,900 m) in northern Thailand. The plant can be found at Doi Chiang Dao Wildlife Santuary and Doi Inthanon National Park in Changwat Chiang Mai. Taxonomically, it is closely related to H. hookeri C. B. Clarke ex Baker. However, the labellum of H. aureum C. B. Clarke & Mann ex Baker is not clawed and the ligule is shorter. [Figs. 1 & 2] 2. H. biflorum Sirirugsa & K. Larsen, Nord. J. Bot. 15 (1995) 303. Type: Murata et al. T-16946 (holotype L) This species was described in 1994 (Sirirugsa & Larsen, 1995). It is so far found only on limestone clefts around Khao Phra Wo ( elevation ca. 750 m) in Mae Sot, Changwat Tak. The plant is allied to H. hirsutissimum Holttum, but having shorter bracts and calyces, and longer corolla tubes, staminodes, and anthers. It was described that each bract subtended two flowers, hence the specific epithet çbiflorumé. However, investigation of living specimens from the type location revealed 2-4 flowers per bract. [Fig. 3] 3. H. coccineum Buch.-Ham. ex Sm. in Ress Cyclop. 17 (1811) n. 5. Type: Buch. Ham. s.n. (lectotype K) This unique reddish-orange flowered species was found in mixed deciduous or evergreen forests in high altitude mountain ranges in northern Thailand. The plant can be easily distinguished by its bright crimson, dull brick red, or salmon-red flowers. This species can be seen in Doi Chiang Dao Wildlife Santuary, Doi Ang Khang and Doi Suthep-Pui National Park (Changwat Chiang Mai), Doi Pui (Changwat Mae Hong Son), Doi Khun Chae (Changwat Chiang Rai). The leaves of the Thai specimens are varied in length and width and the inflorescence are also found to be varied in length. [Figs. 4 & 5) 4. H. collinum Ridl., J. Str. Br. Roy. Asiat. Soc. 32 (1899) 103. Type: Ridley s.n. (holotype SING) This species was first described from Peninsular Malaysia in 1899 based on the specimen collected from peninsular Malaysia. The plant can be easily recognized by its hairy ligule, bract, calyx tube, and ovary, lax inflorescence, 3-4- flowered bracts. The labella of this plant are white, obovate and deeply bilobed, while the stamen is orange to salmon red and longer than the labellum. The plant has been collected in Khao Kuap on the Thai- Cambodian border in Changwat Trat of southeast Thailand. The plant has also been found in peninsular Thailand.