Bulbophyllum paramjitii Agrawala, M.U.Sharief & B.K.Singh, 2016

Agrawala, Dinesh K., Sharief, Mohamed U. & Singh, Basant K., 2016, Bulbophyllum paramjitii (Orchidaceae: Epidendroideae: Malaxideae): a new species from Sikkim Himalaya, India, Phytotaxa 273 (1), pp. 72-76 : 72-75

Bulbophyllum paramjitii Agrawala, M.U.Sharief & B.K.Singh , sp. nov. ( Fig. 1 , 2A )

Type: INDIA . Sikkim: East District, near Bhusuk , 1550 m, 27°20’52.49” N ; 088°39’28.36” E, 26 March 2015, (flowered in cultivation at Gangtok, August 2015), Sharief & Singh 37938 (holotype: BSHC!).

Diagnosis: This new species differs from Bulbophyllum subtenellum in having well developed leaves present during flowering; a rugose labellum apex, apical margin rolled to form a pouch and disc with three prominent calli, of which the middle one is confined to base and the two laterals extending up to the middle of apical lobe.

Small, caespitose, epiphytic herbs, up to 2 cm tall (including pseudobulbs, leaves and flowering shoots). Rhizome slender, concealed below the closely placed pseudobulbs. Pseudobulbs 3.0–4.0 × 2.5–3.0 mm, oblong-globular, oblique, slightly bilaterally compressed, jointed end to end and forming a mat, smooth when young, wrinkled at maturity, bearing a solitary apical leaf in a lateral position. Leaves 5–10 × 3–4 mm, elliptic-ovate, entire, acute, sessile, slightly oblique at base with somewhat twisted appearance. Flowering shoot (scape) slender, arising from base of mature pseudobulbs, looking like a moss capsule when in bud, elongating with opening of the flower, up to 10 mm long including the solitary flower; peduncle sheathed below with a 2 mm long, membranous, clasping sheath. Floral bract ca. 1 mm long, tubular, membranous, clasping the pedicel. Pedicel slender, ca. 4.5 mm long including the ovary, abruptly curved below ovary, swollen in the ovary region. Flowers 2.0– 2.5 mm in diameter, facing downwards, sepals and petals orange-yellow with dark orange veins, veins slightly raised dorsally; lip uniformly dark orange. Dorsal sepal 2.2 × 1.5 mm, ovate-oblong, entire, obtuse, 3-veined, glabrous. Lateral sepals 2.2 × 1.8 mm, ovate-triangular, slightly oblique at base, entire, sub-acute to obtuse, 3-veined; mentum 2 mm long, broadly conical. Petals 1.8 × 0.9 mm, oblong-elliptic, entire, sub-acute, 1-veined, membranous. Labellum 2 × 2 mm, movably attached to the apex of and hinged on the column-foot through a short, hyaline claw, strongly deflexed from middle, trilobed; side lobes 1 × 1 mm, erect, rounded; midlobe 1.0 × 1.1 mm, cordate when spread, margin rolled back forming a pouch at dorsal side, apex obtuse, upper surface rugose; disc with three short, raised calli, middle one confined to the base, the lateral two positioned at junction of side lobes and midlobe. Column ca. 1mm long, dark orange, with a long, up curved foot; stelidia 2, ca. 0.5 mm long, nearly as long as the column proper, pointed towards the apex; anther 2-lobed, apiculate, rugose; pollinia 2, yellow, with broad viscidium; stigmatic cavity obcordate, occupying large part of the column; rostellum broad, hyaline. Capsule 6 × 3 mm, obpyriform, strongly ridged, with marscescent perianth parts at apex.

Distribution and habitat: Epiphytic on main tree trunk of Schima wallichii ( Theaceae ) at 1550 m. The small, crowded pseudobulbs give a mat-like appearance and cannot be recognized from a distance. This species is known from the type locality only.

Etymology: The species is named in honor of Paramjit Singh, an eminent taxonomist and Director of Botanical Survey of India , who worked extensively on Sikkim Himalayan flora.

Phenology: Flowering August–October; fruiting October onwards.

Conservation status: This species is so far known from a single patch at the type locality ( Fig. 3 ). Data on its past population and rate of population decline are not available for application of Criteria A of IUCN (2012). Its Extent of Occurrence (EOO) and Area of Occupancy (AOO) can be estimated as 4 km 2 (Criteria B) by taking the minimum grid size of 2 × 2 km. Being an epiphytic species, its survival highly depends on that of the host tree and, therefore, the number of mature individual (Criteria D) is calculated as one (as it was found only on one tree). The quality of habitat is declining because of development and urbanization. Sexual reproduction in nature depends on the availability of pollinator(s) and suitable mycorrhiza. Climate change is one of the plausible threats for this species. Number of locations is one (B2a) and a continuous decline in area, extent, and quality of habitat is projected [B2b(iii)], considering the threats mentioned above. In view of the above, and as per the IUCN (2013) guidelines, the threat perspective of this species can be assessed as ‘Critically Endangered’ [CR B1ab(iii)+2ab(iii); D].

Discussion: Seidenfaden (1979) emphasized the number of veins in lateral sepals as an important character when describing Bulbophyllum subtenellum . The type specimen and illustration ( Fig. 2B,C ) evidently shows three unbranched veins in the lateral sepals, absence of leaves during flowering and lack of a callus on the labellum. Seidenfaden (l.c.) also mentioned the labellum with a fat, glossy, semi-globular apical portion. Bulbophyllum paramjitii matches this in every aspect but has well-developed leaves at flowering, three prominent calli on the labellum and its semi-globular lip apex is rugose. It is also closely related to Bulbophyllum menghaiense Tsi (1981:109) from southern Yunnan ( Fig. 2D ), but the latter has characteristically larger floral parts, differently shaped sepals, labellum with a triangular basal portion and a linear apical portion ending in a fleshy apex without a callus.

Figures

FIGURE 1. Bulbophyllum paramjitii. A. Habitat (not to scale). B. Habit. C. Inflorescence. D. Flower (front view). E. Flower (lower side view showing the pouch of the labellum). F. Flower (lateral view). G. Sepals and petals (ventral surface). H. Sepals and petals (dorsal surface showing the slightly raised veins). I. Flower without labellum (not to scale). J. Pedicel, ovary and labellum (lateral view). K. Labellum (lateral view). L. Labellum (flattened). M. Labellum (uncompressed front view). N. Column (lateral veiw). O. Column (front view). P. Anther and pollinia. Q. Pollinia (separated and enlarged). Photograph by D.K. Agrawala from the holotype (Sharief & Singh 37938).

FIGURE 2. A. Fruiting specimens of Bulbophyllum paramjitii. B. Illustration of Bulbophyllum subtenellum (after Seidenfaden, 1979). C. Type specimen of Bulbophyllum subtenellum (kept in spirit at C). D. Illustration of Bulbophyllum menghaiense (after Chen & Vermeulen 2009).

FIGURE 3. Distribution of Bulbophyllum paramjitii.