Bulbophyllum section Piestobulbon Schltr., Bot. Jahrb. Syst. 58 (1923) 140
Small to medium-sized epiphytes. Rhizomes patent to stiffly pendulous (creeping in Bulbophyllum fasciculiferum); rhizome bracts thin, approx. glabrous to minutely colliculate, caducous including the veins. Roots mainly near to the base of the rhizomes, growing backwards towards the substratum over or alongside the rhizome (? Spreading in Bulbophyllum fasciculiferum), glabrous or slightly and minutely hirsute locally. Pseudobulbs conspicuous compared to the size of the plant, 1-leafed, with shoots sprouting at its basal node and free, not fused to the pseudobulb. Leaves persistent, thick, veins inconspicuous. Inflorescences sprouting at nodes along the length of the rhizome; eventually densely fasciculate, 1-flowered. Peduncle shorter than the pseudobulbs, peduncle bracts c. 3, the upper approx. at half-way the peduncle. Flowers per sympodium 1 open at a time; floral bracts tubular; pedicel with the basal node well above the attachment of the floral bract, longer than the ovary. Sepals free, of approx. equal length, 3— 7.5 mm long, elliptic to ovate, acute to acuminate, margins entire, glabrous or ciliate, thin, 3-veined, surface glabrous. Petals 0.7— 1.7 mm long, elliptic to oblong-spathulate, to ovate, obtuse to acuminate, margins entire to erose, glabrous or papillose with elongated papillae or ciliate; thin, 1-veined, surface glabrous. Lip mobile on a thin ligament, without auricles, 3— 6 mm long, approx. ovate, unguiculate, margins approx. entire, glabrous or distally ciliate; adaxially usually without ridges, (approx.) concave close to the base, this cavity in front bordered by a transverse ridge which is notched half-way or has a distinctly concave crest line, in front of this surface (somewhat concave grading into) convex (with a second, retrorse, transverse ridge in Bulbophyllum paucisetum), surface approx. glabrous, or long-hirsute distally (with numerous transverse ribs and with a tuft of papillae distally in Bulbophyllum paucisetum); abaxial surface glabrous, somewhat transversely verrucate or hirsute. Column straight (not incurved), with rostellum front (somewhat) receding in between the stelidia, stigma wide, without keels inside, proximally somewhat protruding or not, column foot not widening towards its top, but with a distinct median tooth close to the tip, free part absent or short. Stelidia shorter than 1/2 of the length of the column; approx. triangular, upper margin with or witout a slight, deltoid, rounded tooth, lower margin with a more distinct, patent to antrorse, deltoid to triangular, rounded tooth. Anther abaxially with a low rounded crest, front not concave, front margin somewhat drawn out. Pollinia 4, the inner more than half as long as the outer; without appendages.
New Guinea: 4 taxa. Altogether 5 provisionally accepted taxa (7 names): New Guinea, West Pacific.
Doubtfully different from section Codonosiphon. Differences include: column not incurved, transverse ridge on the adaxial side of the lip notched or with a markerdly concave crest line, and positioned more distally on the surface of the lip and not as neatly appressed against the face of the column as in section Codonosiphon. A few species here included in section Codonosiphon may actually belong in section Piestobulbon: Bulbophyllum mystrophyllum, Bulbophyllum pemae.
The following taxa in this program belong to this Section: