e-Flora of Thailand
Volume 16 > Part 2 > Year 2023 > Page 585 > Zingiberaceae > Hedychium
7. Hedychium densiflorum Wall.wfo-0000435868
Hooker’s J. Bot. Kew Gard. Misc. 5: 368. 1853; Baker, Fl. Brit. India 6: 227. 1892; Schumann, Pflanzenr. IV, 46 (Heft 20): 49. 1904; Smith, Fl. Bhutan 3(1): 202. 1994; Wu & Larsen, Flora of China 24: 373. 2000. Fig. 26 D, Plate LXVII: D.
Accepted Name : This is currently accepted.
Description : Epiphytic to lithophytic herb; rhizomes ovoid to ovoid-oblong, 1–4 cm diam. Leafy shoots 30–100 cm tall, 4–6 mm diam.; bladeless sheaths 1–4; leaf sheaths green, sometimes with a thin red line along margins; ligule short, green to red, entire or bilobed, 0.5–3 by 4–5 mm, glabrous, apex obtuse; blades 7–16, lanceolate, lanceolate-oblong or elliptic-oblong, 10–21.1 by 1.4–3.9 cm, glabrous, base cuneate, apex long acuminate; sessile or petiolate, to 5 mm long. Inflorescence a terminal spike, 3.5–8 cm long, laxly to densely 13–25-flowered; peduncle 1.5–2.5 cm long; bracts pale green, apparently shorter than calyx, not imbricate, lanceolate to lanceolate-oblong, (0.4–)1–1.5 by 0.4–0.5 cm, apex obtuse to acute, glabrous, 1-flowered; bracteoles tubular, 4–8 mm long, 2–4 mm diam., glabrous, apex acute. Flowers resupinate, golden yellow to bright orange, ca 2.5 cm long; ovary 2–3 by 2 mm, glabrous; style filiform, ca 2.2 cm long; stigma ciliate; epigynous glands 0.8–2 mm long; calyx 0.8–1 cm long, ca 2 mm diam., deeply split on one side, apex shallowly trilobed, glabrous; floral tube yellow to orange, base paler, 0.8–1.3 cm long, glabrous, corolla lobes linear, 0.7–1 by 0.1–0.3 cm, glabrous, apex hooded, margin involute; lateral staminodes broadly scimitar-shaped, oblanceolate, to oblong, 0.7–1.1 by 0.2–0.4 cm, apex rounded to acuminate, sometimes obliquely bifid to slightly crenate; labellum sessile to shortly clawed, obovate, ovate to broadly elliptic, 0.7–1.1 by 0.4–0.8 cm, apex deeply bilobed to ⅔–¾ of the length, lobes 1.5–3 mm broad, apex rounded; stamen ± equal or a little longer than labellum; filament 5–8 mm long; anther elongate, 3–5 mm long. Fruit subglobose to trilobed, 0.8–1.6 by 1.1–1.6 cm, glabrous; seeds 15–20, red, ellipsoid to oblong, 5–7 by 2–3 mm, aril red.
Thailand : NORTHERN: Mae Hong Son (Khun Yuam), Chiang Mai (Doi Chiang Dao, Doi Inthanon, Omkoi); Phitsanulok (Phu Soi Dao).
Distribution : NE India (Sikkim – type), E Nepal, Myanmar, China (Yunnan – type of Hedychium sinoaureum).
Ecology : Epiphytic or lithophytic on limestone in lower montane forests, at 1,500–2,100 m alt., rather rare.
Vernacular : Ta hoen kham (ตาเหินคำ )(Northern).
Notes: Hedychium densiflorum is the smallest species of Hedychium found in Thailand. In NE India and Nepal, where this species grows terrestrially, the plants are much larger. Further southeast, they become smaller where they grow as lithophytes or epiphytes. Size variation in different habitats has also been observed in other species, e.g., H. ellipticum and H. villosum. Phu Soi Dao, the highest sandstone mountain in Phitsanulok province, is the south-easternmost distribution of H. densiflorum where the plants are the smallest, ca 30 cm tall.
Some authors in India recognise Hedychium aureum C.B.Clarke & G.Mann ex Baker as a good species but we regard it as part of the wide variation within H. densiflorum.