Habenaria nepalensis Kolan., 2016

Kolanowska, Marta, 2016, A new species of Habenaria (Orchidaceae) from Nepal, Phytotaxa 261 (1), pp. 92-96 : 92-93

Habenaria nepalensis Kolan. , sp. nov. ( Figs 1–3 )

This new species is similar to H. plantaginea from which it is distinguished by the form of the lip middle lobe which is trilobulate, with lobules triangular to triangular-ovate, obtuse to acute.

Type :— NEPAL. Ramnagar / Chikana, 300 m, 1995, Wesche 3139 (holotype: BM!; isotype: BM!; the holotype is the specimen on the right side of herbarium sheet BM 000074168 ) .

Erect herbs, 16–22 cm tall. Tuber not seen. Leaves 4–6, subbasal, sheathing at the base, 4.5–9.0 × 1.0– 2.5 cm, ellipticlanceolate to oblanceolate, acute. Stem bracts 2–3, 16–20 mm long, ovate, acuminate. Inflorescence laxly 12–15-flowered, rachis glabrous. Floral bracts 15–22 mm long, ovate, acute. Ovary glabrous, 15–25 mm long. Dorsal sepal about 4 × 3 mm, ovate, rounded at the apex, 3-veined. Lateral sepals 5.0–5.5 × 3.0 mm, obliquely ovate, obtuse, 3-veined, lateral vein bifid. Petals 4.5 × 2.0 mm, obliquely lanceolate-elliptic, obtuse, 1-veined. Lip 14.5 × 10.0–12.0 mm, trilobed, minutely clawed; lateral lobes semiovate, obtuse to subacute, margins denticulate; midlobe trilobulate, lobules subequal in size, triangular to triangular-ovate, acute to obtuse margins entire. Spur 28–40 mm long, cylindric, slightly swollen at the apex. Gynostemium about 2 mm long, antherophores subequal in length to stigmatophores.

Etymology:— The specific epithet refers to the country of the type specimen.

Taxonomic notes:— In habit and tepal shape, the new species resembles Habenaria plantaginea , known from India, Sri Lanka and Nepal. The occurrence of this orchid in Nepal was reported from 450–2500 m ( Rokaya et al. 2013). Habenaria nepalensis is, however, easily distinguished from this and all other Asian species by its trilobulate lip midlobe. Noteworthy, the lateral lobules of the lip midlobe are visible exclusively when the lip is observed from the back. Among several dozen herbarium specimens of H. plantaginea examined during the study, no other plant with such distinguishable lip was found.

Although in most Neotropical species of Habenaria morphology of perianth segments is consistent, and no significant differences in the flower structure are observed among populations, numerous examples of variable taxa have previously been reported from the Old World (e.g. Summerhayes 1968). Most often the abnormalities concern reduction of the spur and/or lip lateral lobes length (e.g. Segerback 1983). The superficial examination of herbarium specimens may lead to redundant descriptions of new taxa. An example of this is H. anomala Dockrill (1965: 150) , which was described as a new species differing from H. xanthantha Mueller (1869: 16) by the spurless flowers ( Dockrill 1965). A detailed examination of the type specimens of the latter revealed that flowers with prominent spur are arranged in the same inflorescence together with flowers with reduced spur. Except for variation of the lip lateral lobes and spur length, some plants with abnormal gynostemium structure were reported in the previous studies ( Seidenfaden 1992, Kurzweil et al. 2009).

Habenaria nepalensis does not appear to be monstrous form of H. plantaginea . The lip middle lobe lobing that constitutes the most striking difference between these species is persistent and found in all examined flowers. Moreover, the form and size of the lip lateral lobes as well as spur length, which are the most common deviations from normally developed flowers, are similar in both species. Also the gynostemium of H. nepalensis does not show any morphological abnormalities.

Figures

FIGURE 1. Habenaria nepalensis Kolan., dissected flower. A. Dorsal sepal. B. Petal. C. Lateral sepal. D–E. Lip. F. Gynostemium. G. Ovary and spur. Scale bars = 2 mm. Drawn by N. Olędrzyńska from the holotype.

FIGURE 2. Habenaria nepalensis, habit. Scale bar = 5 cm.