Bulbophyllum section Brachystachyae Benth. & Hook.f., Gen. Pl. 3 (1883) 504
Small to medium sized epiphytes. Rhizomes creeping, or erect to pendulous; rhizome bracts thin, glabrous to colliculate, caducous including the veins, or veins slightly to distinctly persistent as (thick) fibres. Roots sprouting along the rhizome or mainly below the pseudobulbs, spreading; in species with a patent to pendulous rhizome below the older pseudobulbs only, growing over or alongside the rhizome towards the substrate; glabrous to finely hirsute locally. Pseudobulbs conspicuous to minute compared to the size of the plant, 1-leafed, with shoots usually sprouting from its basal node and free, not fused to the pseudobulb or, if pseudobulbs minute, also fused to the pseudobulb for up to the length of the latter. Leaves persistent, thick, veins inconspicuous. Inflorescences usually sprouting from the (sub-)basal node of the pseudobulb, also from nodes along the entire rhizome, single, racemose with flowers spirally arranged. Peduncle shorter than the pseudobulbs to longer than the leaves, peduncle bracts 3— 5, scattered with the upper slightly above half-way the peduncle or lower. Rachis (distinctly) thickened or not. Flowers per inflorescence many open at a time; floral bracts not amplexicaul; pedicel with the basal node level with the floral bract attachment, as long as the ovary or shorter. Sepals: the median free, the laterals usually more or less adherent to connate along their lower margin, 0.9— 1.5 times as long as the median; 3— 12 mm long, (ob-)ovate to elliptic to triangular, rounded to acuminate, margins entire, glabrous to papillose to ciliate; thin to thick, abaxially not or hardly keeled, 3-veined (the laterals sometimes 5-veined), surface glabrous to papillose to hirsute. Petals 1.1— 4 mm long, spathulate, elliptic to (ob-)ovate, to triangular, rounded to shortly acuminate, margins entire to distally deeply erose, glabrous to papillose to ciliate; thin, 1— 3-veined, adaxial surface glabrous to papillose distally. Lip mobile on a thin ligament, without auricles near the ligament but sometimes with auricles well above the lip base, undivided, 1— 5.2 mm long, panduriform, spathulate, approx. circular, elliptic to oblong, (ob-)ovate to hastate, margins entire, glabrous to papillose to ciliolate; adaxially usually concave towards the base, sometimes with a narrow transverse ridge just above the ligament, without ridges or with two more or less converging flexural ridges which are often highest and angular near the base, top part slightly to distinctly convex, surface glabrous to papillose; abaxial surface approx. glabrous or with a papillose patch in the centre. Column with rostellum front receding in between the stelidia, stigma large, without keels inside, proximally not or very slightly protruding, column foot tapering towards its top, free part virtually absent, sometimes very short; with or without a slight median thickening. Stelidia shorter to longer than 1/2 of the length of the column; usually short but not vestigial, approx. deltoid to triangular, upper margin usually with a slight to distinct, deltoid to triangular, widely rounded to acuminate tooth (sometimes much larger than the stelidia and widely overtopping this), lower margin with a deltoid to triangular, rounded to acuminate wing or tooth. Anther abaxially with a (low) rounded crest, front usually more or less concave, front margin drawn out into a beak. Pollinia usually 4, with the inner slightly less than half as long as the outer or longer; without appendages.
Distribution
New Guinea: 2 taxa. Altogether 57 provisionally accepted taxa (80 names): India and Sri Lanka to China, Southwards to Java, east to West Pacific. In Maluku and Eastwards represented by few species only.
Notes
The differences between section Brachystachyae and section Stachysanthes are often obvious in the field (raceme dense with flowers arranged in a regular pattern, or lax and flowers with lateral sepals appressed to the rachis vs. raceme dense or lax, with patent flowers not arranged in a regular pattern; flowers with purple colouring vs. flowers without purple colouring; lateral sepals together forming a dish- or bowl-shaped structure around the lip vs. lateral sepals spreading), but truly diagnostic differences are difficult to find. Best are: upper margin stelidia usually with a slight to distinct wing or tooth vs. upper margin stelidia usually without wing or tooth; pollinia usually 4 vs. pollinia usually 2.
The following taxa in this program belong to this Section:
Bulbophyllum atrorubens
Bulbophyllum globiceps