Volume 16 > Part 2 > Year 2023 > Page 579 > Zingiberaceae > Hedychium

1. Hedychium biflorum Sirirugsa & K.Larsenwfo-0000435621

Nordic J. Bot. 15: 303. 1995; Wongsuwan & Picheansoonthon, J. Roy. Inst. Thailand 3: 131. 2012. Fig. 25 A–B, Plate LXVII: A.

Accepted Name : This is currently accepted.

Description : Lithophytic herb. Leafy shoot 80–150 cm tall, 1.5–2 cm diam.; bladeless sheaths 2–3; leaf sheaths green, glabrescent; ligule oblong, 3–6 by 1.3–2 cm, membranous, sparsely pilose, apex rounded to acute; blades 5–7, elliptic-oblong, oblong-lanceolate, to elliptic lanceolate, 30–54 by 5–12 cm, glabrous above, glabrous to sparsely villous below, base rounded, apex acuminate; sessile. Inflorescence a terminal spike, 13–28 cm long, lax to dense; peduncle 4–5 cm long, rachis visible, green, densely villous; bracts 20–26, not imbricate, light green translucent, ovate to oblong, 1–1.4 by 0.6 cm, pubescent, apex acuminate, 1–3-flowered; bracteoles broadly ovate to triangular, 1–1.2 by ca 1 cm, pubescent, apex acute. Flower resupinate, white with orange-red stamen, turning to yellow with age, fragrant; ovary ovoid, 4 by 2–3 mm, densely pubescent; style filiform, ca 6 cm long; stigma ca 0.5 mm diam., margin ciliate; epigynous glands 2, linear, ca 3 mm long; calyx yellowish green, 1.5–1.6 cm long, 2–2.5 mm diam., densely pubescent, apex bifid to trilobed; corolla yellowish green, glabrous; floral tube ca 3 cm long, lobes linear, 3.4–3.8 cm long; lateral staminodes linear-lanceolate, 3.6–4 by 0.4–0.5 cm, apex narrowly obtuse, usually bent downwards at anthesis; labellum sessile, elliptic-oblong, 2.8–3.4 by 1.4–2 cm, apex deeply divided to ½–⅔ of its length or almost to base, apex of lobes acuminate, wavy and often twisted distally, outer margin irregularly crenate-dentate, rarely entire, bent downwards at anthesis; stamen orange-red, less than twice as long as labellum; filament 4.8–5.4 cm long, straight to slightly downcurved; anther orange-red, ellipsoid, 5–9 by 2–3 mm. Fruit subglobose-oblong, 1–1.2 by 0.8–1.1 cm, slightly trilobed; seeds many, red, ellipsoid-orbicular, 5–6 by 2–3 mm, aril orange-red.

Thailand : NORTHERN: Tak (Tha Song Yang – type: Murata T-16946, holotype -L, isotypes -AAU BKF).

Distribution : Endemic.

Ecology : On limestone cliffs in dry evergreen forests, 700–900 m alt.

Vernacular : Hong hoen (หงส์เหิน), ta hoen phawo (ตาเหินพะวอ), ta hoen song dok (ตาเหินสองดอก).

Notes: In Thailand, Hedychium biflorum is most closely related to H. gomezianum but easily distinguished by having 1–3 resupinate flowers per bract (vs 1, non-resupinate) which then apparently has its stamen sitting above the other floral parts (vs at bottom). The population at Tha Song Yang, Tak is only 10 km from the nearest limestone mountain in Myanmar, across the Moei river so it is likely to occur there too.