Volume 12 > Part 2 > Year 2014 > Page 495 > Orchidaceae > Epipactis

Epipactis flava Seidenf.wfo-0000952029

Dansk Bot. Ark. 32(2): 116, fig. 71. 1978; Sittisajjadham, Wild Orchids Thail.: 243, colour photos on pp. 242–243. 2006; Nanakorn & Watthana, QSBG (Thai Native Orchids 2): 62, colour photos on pp. 62–63. 2008; H.A.Pedersen et al., Bot. J. Linn. Soc. 172: 368, fig. 1–3. 2013. Fig. 273.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Leafy shoots densely gregarious from a branched, creeping rhizome, 18–85 cm tall; stem bearing 2–3 cataphylls, 4–7 sheathing foliage leaves and 0–2 small, non-sheathing leaves. Foliage leaves ovate to elliptic or linear-lanceolate, acute to acuminate, 1.7–11.2 by (0.3–)0.5– 5.8 cm. Inflorescence 1- to 14-flowered; rachis flexuous, 3.5–21 cm long; floral bracts spreading to suberect, ovate to lanceolate or elliptic, acute to acuminate, 5–47 mm long. Flowers long pedicelled, wide-open, mainly greenish-yellow (sepals and petals often with maroon margins, labellum cream to pale yellow and often with orange to maroon markings/suffusion). Sepals shallowly boat-shaped; dorsal sepal lanceolate (to lanceolate-oblong), (sub)acute, 8–10.1 by 2.5–3.9 mm; lateral sepals obliquely ovate to falcately lanceolate, acute, 8.9–11 by 2.7–4.6 mm. Petals recurved (apices often meeting behind the dorsal sepal), lanceolate to oblong, obtuse to rounded, 7–9.4 by 2.3–3.8 mm. Labellum 8.3–9.8 mm long, 6.3–8.2 mm wide across side lobes when flattened; hypochile concave with 2 erect, obliquely oblong to subtriangular, rounded side lobes, in its proximal to middle part ornamented by 2 adjoining keels furnished with tiny orange warts and ending in 2 oblongoid calli; epichile elastically attached, broadly oblanceolate to oblong-subspathulate, obtuse to rounded, ornamented by 2 marginal ridges proximally and a small shiny drop-like callus just above the middle. Column 5.4–6.2 mm long; stigma with 2 low swellings at base. Ovary (including pedicel) slenderly fusiform, 11–17 mm long.

Thailand : NORTHERN: Nan (Mae Charim), Tak; SOUTH-WESTERN: Kanchanaburi (Tha Khanun – type: Kerr 0261, lectotype -C, isolectotypes -BK K).

Distribution : Myanmar, Laos, Vietnam.

Ecology : Rheophytic in stream beds, often forming extensive colonies; ca 100–300 m alt. Flowering: January–March.

Vernacular : Kluai mai nam (กล้วยไม้น้ำ).

Notes: When recently describing Epipactis dickasonii, based on an old collection from Myanmar, Ormerod (2012) compared his new taxon with E. flava s.s. and E. atromarginata. He found that it differred from both in the ornaments of the hypochile – and from E. atromarginata in the epichile being trilobulate. Ormerod was probably unaware of a related paper (Pedersen et al., 2013) which was then in press. In that paper, we reduced E. atromarginata to a synonym of E. flava due to the lack of any distinguishing character. In E. flava s.l., both the ornaments of the hypochile and the shape of the epichile are considerably more variable than previously recognized (Pedersen et al., 2013); and when comparing Ormerod’s description and illustration with the observations reported in our recent paper, E. dickasonii evidently falls within the morphological range of E. flava. Consequently, I have added E. dickasonii as a new synonym above. Its type represents the only known find of E. flava in Myanmar.

Pedersen et al. (2013) provided detailed information on the occurrence and highly specialized ecology of the strictly rheophytic Epipactis flava.