Bulbophyllum orthoraphe 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 : 309

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

( Fig. 6 )

TYPE: Papua New Guinea, Enga Province, Kandep Range, Mt. Leyan near Laiagam , ca. 3000 m alt., Jongejan cult. 765 (holotype L!, spirit material).

DIAGNOSIS. Shares the clustered growth, combined with a distally not attenuated lip without sharply outlined patches of papillae or hairs with Bulbophyllum dischorense Schltr. and B. muriceum Schltr. , from which it differs by the oblong (versus triangular) petals and by the straight (versus sigmoid) stelidia; with B. meliphagirostrum Van Royen , from which it differs by the wider lip (ratio length/width 2.2–3.4, without spreading, versus 5–8) and by the shorter petals (2.2– 3.2 mm long versus 4–5 mm long).

Small epiphyte with creeping rhizomes and spreading roots. Rhizome 1.0–2.0 mm diam., sections between pseudobulbs 0.1–0.5 cm long, arising from the basal node of the pseudobulb; rhizome scales thin, little persistent. Pseudobulbs distinct, ellipsoid to ovoid, 0.6–1.2 × 0.1–0.5 cm, hardly angular. Leaf: petiole 0.1–0.3 mm long; blade elliptic to obovate, 1.2–2.5 × 0.4–0.6 cm, ratio length/width 2.6–6.4; subacute. Inflorescences single or a few together, 4.9– 6.3 cm long, 1-flowered. Peduncle 3.0–4 0 cm long, scales 3–4. Floral bracts 2.5–5.0 mm long. Flowers: pedicel plus ovary 7–10 mm long, basal node 1.5–2.0 mm above the floral bract attachment. Median sepal free, recurved, (ovate-)triangular, 9.5–13.0 × 1.5–2.5 mm, ratio length/width 4.8–6.4; acute(-acuminate), margins entire, ciliolate, surface glabrous; 3-veined. Lateral sepals as the median but triangular, 12.0–15.0 × 1.8–2.7 mm, ratio length/width 4.8–6.7, upper margin glabrous. Petals porrect, oblong to (ob-)ovate, 2.2–3.2 × 0.8–1.4 mm, ratio length/width 2.0–3.0; obtuse to acute-acuminate, margins entire, ciliolate, surface glabrous; 1–2-veined. Lip approx. porrect, ovate, 3.7– 4.3 × 1.1–1.9 mm, ratio length/width 2.2–3.4 (without spreading); rounded, margins entire, approx. glabrous to finely papillose in the basal half (but glabrous close to the base); thick and soft; adaxially concave in the proximal 2/5–1/2, increasingly convex distally, adaxial surface with two vaguely outlined (minutely) papillose patches towards the margins in the basal half, otherwise glabrous; abaxially with a median furrow along its entire length, otherwise convex, surface minutely papillose proximally. Column including stelidia 1.5–1.6 mm long, stigma wide-obovate, proximally not protruding from the column face, foot distally widened, with spreading, rounded lateral teeth. Stelidia porrect, narrowly triangular, 0.4–0.6 mm long, acute. Pollinia 4, the inner more than half as long as the outer.

COLOURS: flowers red-purple.

ETYMOLOGY: orthos (Greek) = straight, raphe (Greek) = needle, referring to the straight stelidia.

HABITAT AND ECOLOGY: epiphyte in moss forest. Elevation ca. 3000 m.

Figures

FIGURE 6. Bulbophyllum orthoraphe 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. Column and lip, lateral view. g. Column, frontal view. h. Anther, above: adaxial side, below: abaxial side. Drawn from Jongejan cult. 765 by © J.J. Vermeulen, from spirit material.