Bulbophyllum ischyron J.J.Verm., Schuit. & de Vogel

Vermeulen, Jaap J., Schuiteman, André & De Vogel, Edward F., 2020, Sixteen new species of Bulbophyllum section Polymeres (Orchidaceae) from New Guinea, Lankesteriana 20 (3), pp. 301-330 : 304-307

Bulbophyllum ischyron J.J.Verm., Schuit. & de Vogel , sp. nov.

( Fig. 4 )

TYPE: Indonesia, Papua Province, Damarga Lakes , 2500–4000 m alt., Jan. 1994, Wickenden 36 (holotype E!).

DIAGNOSIS. Most similar to Bulbophyllum dologlossum , differs by the acute sepals, the 4-veined (versus 1-veined) petals, the ovate-oblong lip, gradually tapering without narrowed parts towards the apex, with only 2 (versus 4) ridges on the adaxial side, and the straight stelidia.

Rather small epiphyte with creeping rhizomes and spreading roots. Rhizome ca. 4 mm diam., sections between pseudobulbs arising from the basal node of the pseudobulb; rhizome scales thick, weathering to woolly fibres, persistent. Pseudobulbs distinct, ovoidcylindrical, ca. 2.5 × 0.9 cm, hardly angular. Leaf: petiole ca. 12 mm long; blade thick, obovate-oblong, ca. 6.4 × 0.7 cm, ratio length/width 9.1–9.2; subacute. Inflorescences single or few together, ca. 24 cm long, 1-flowered. Peduncle ca. 17 cm long. Floral bracts 11–12 mm long. Flowers: pedicel plus ovary ca. 4 cm long, basal node ca. 9 mm above the floral bract attachment. Median sepa l free, recurved, ovate, ca. 24.0 × 9.0 mm, ratio length/width 2.6–2.7; acute, margins entire; minutely papillose; 3(–4)-veined. Lateral sepals as the median but triangular, 28.0– 11.5 mm, margins glabrous. Petals porrect, ovate-oblong, ca. 10.0 × 7.0 mm, ratio length/width 1.4–1.5; obtuse, margins slightly erose, ciliolate, surface glabrous; 4-veined. Lip slightly recurved near the base, ovate-oblong, ca. 12.0 × 4.0 mm, ratio length/width ca. 3 (without spreading); obtuse, margins approx. entire, densely hirsute towards the base, glabrous towards the apex; thick; adaxially with two slightly converging ridges, rather close together and with a rather narrow furrow in between, which continue up to ca. 3/5 of the length of the lip, where they grade into the convex lip surface, adaxial surface unevenly papillose-hirsute towards the margins in the basal half of the lip, glabrous elsewhere; abaxially distinctly convex, deeply furrowed and unevenly papillose-hirsute proximally, slightly concave and glabrous distally. Column including stelidia ca. 5 mm long, stigma narrowly obverse-triangular, proximally not protruding from the column face, foot distinctly widened, with patent, obtuse lateral teeth. Stelidia straight, narrowly triangular, ca. 2.6 mm long, acute. Pollinia 4.

COLOURS: flowers ‘pale’.

ETYMOLOGY: ischuros (Greek) = sturdy, referring to the thick leaf blade.

HABITAT AND ECOLOGY: large plant growing in shrub. Elevation 2500–4000 m.

Figures

FIGURE 4. Bulbophyllum ischyron J.J.Verm., Schuit. & de Vogel. a. Habit. b. Flower. c. Flower analysis, from left to right: median sepal, petal, lateral sepal, lip. d. Petal. e. Lip, left: adaxial side, right: abaxial side. f. Lip, lateral view. g. Column, lateral view. h. Anther, left: abaxial side, right: adaxial side. Drawn from Wickenden 36 by © J.J. Vermeulen, from herbarium material.