Genus Bulbophyllum section Brachypus

Genus Bulbophyllum section Brachypus

Bulbophyllum sect. Brachypus Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1: 700, 765. Type species: Bulbophyllum maxillarioides Schltr. (designated by Van Royen, 1979)

Synonyms:

  • Genus Bulbophyllum Section Gibberanthera J.J.Sm., Nova Guinea 12 (1916) 424

Small to medium-sized epiphytes. Roots sprouting mainly below the pseudobulbs, glabrous or slightly and minutely hirsute locally. Rhizomes (rather) short-creeping; rhizome scales thin, approx. glabrous to minutely colliculate, caducous (with the nerves slightly more persistent). Pseudobulbs conspicuous compared to the size of the plant, 1-leafed, with shoots sprouting at its basal node and free, or fused to the pseudobulb over a very short distance only. Leaves persistent, thick, nerves inconspicuous. Inflorescences sprouting at or somewhat above nodes along the length of the rhizome, usually densely fasciculate, 1-flowered; peduncle shorter than to approx. as long as the pseudobulbs (approx. as long as the leaves in Bulbophyllum ialibuense); peduncle scales 24, scattered along the peduncle; floral bracts tubular. Flowers per sympodium 1 open at a time. Pedicel with the basal node well above the attachment of the floral bract, approx. as long as the ovary or longer. Sepals free, or the laterals (partly) connate, or all three (partly) connate. Lateral sepals not or hardly longer than the median (up to 1.2 times as long as the median in Bulbophyllum ialibuense), elliptic to ovate-triangular, 85.2 cm long, glabrous (minutely papillose-ciliolate in Bulbophyllum phaeoglossum), thin to thick; margins entire; apex obtuse to short-acuminate; 3-9-nerved, surface glabrous or (finely) papillose to hirsute adaxially. Petals fused to the column over a short distance near the base, either over their entire width, or along the upper margin only (free in the group of Bulbophyllum lineolatum, see below), rhombiform, oblong, or elliptic to triangular, 3.8 cm long, glabrous to papillose to ciliolate; thin; margins approx. entire; apex truncate to acute; 1-nerved; glabrous (adaxial surface finely papillose in Bulbophyllum calceilabium). Lip mobile on a thin ligament, without auricles near the ligament, undivided, elliptic to (ob-) ovate, oblong, or hastate, 0.258 cm long, glabrous to papillose or ciliolate; margins approx. entire; adaxially without ridges, or with two (more or less converging) ridges in approx. flexural position; surface approx. glabrous to papillose; abaxial surface glabrous, or with a distinct, finely to coarsely papillose or hirsute patch in the middle part (often combined with an approx. glabrous adaxial side). Column with rostellum front receding in between the stelidia; stigma slit-like to wide, rounded, without keels inside, usually not protruding proximally (protruding in Bulbophyllum ialibuense and in some of the group of Bulbophyllum lineolatum); column foot not or hardly widening nor thickening towards its top, free part short, without lateral teeth at the tip (with small, patent lateral teeth in Bulbophyllum variculosum, Bulbophyllum wollastonii); stelidia shorter to distinctly longer than 1/2 of the length of the column; distinct, triangular to subulate, or narrowly oblong, with or without a patent to antrorse deltoid, obtuse tooth along the upper margin, with at most a slight, rounded widening present along the lower (with a deltoid, obtuse wing in Bulbophyllum variculosum); anther with a high rounded crest, in front not concave, front margin not drawn out; pollinia 4, with the inner ones more than half as long as the outer ones, without appendages.

Colours: Flowers usually white or yellowish or greenish, with or without purple markings, or flowers largely purple; lip bright yellow in some species. .



New Guinea, West Pacific.

Genus Bulbophyllum section Brachypus contains 21 provisionally accepted species (22 names); in New Guinea 20 species.

  • Royen, P. van The Alpine flora of New Guinea 2 (1979) 200
  • Family Orchidaceae
  • Subfamily Epidendroideae
  • Tribe Dendrobieae
  • Subtribe Bulbophyllinae
  • Genus Bulbophyllum
  • Section Brachypus

Diagnostic are the petals which are proximally fused to the column, because that character is best for grouping overall similar species together. Generally, the species are characterized by a short rhizome with clustered pseudobulbs, and short-peduncled flowers. Many species have a distinctly thickened and widened rostellum, sitting as a shield-like structure between the stelidia. The taxonomic value of this character needs investigation, as does the precise delimitation of the section. The inflorescence of Bulbophyllum ustusfortiter is much contracted, and so is the distance between the floral bract and the pedicel node.

In general aspect grading into section Polymeres through species such as Bulbophyllum bombycinum, Bulbophyllum maxillaroides which are here included in the latter. Section Brachypus is kept separate to accomodate a suite of species generally without, or with an indistinctly widened and laterally toothed or winged column foot.

Morphologically, the group of Bulbophyllum lineolatum (Bulbophyllum apiculatum, Bulbophyllum blepharopetalum, Bulbophyllum latibrachiatum, Bulbophyllum lineolatum, Bulbophyllum wollastonii) straddles section Polymeres and section Brachypus in the shape of the column foot. The petals are not fused to the column. The flower shape, in particular the narrowly oblong, strap-shaped, obtuse, stelidia suggests phylogenetic affinity of the species. The group is provisionally included in section Brachypus.

Bulbophyllum section Brechypus in New Guinea contains 25 species and 1 variety:

Bulbophyllum apiculatum
Bulbophyllum blepharopetalum
Bulbophyllum calceilabium
Bulbophyllum cerinum
Bulbophyllum chionanthum
Bulbophyllum galactanthum
Bulbophyllum giriwoense
Bulbophyllum gunteri
Bulbophyllum hansmeyeri
Bulbophyllum ialibuense
Bulbophyllum katjae
Bulbophyllum latibrachiatum
Bulbophyllum latibrachiatum var. epilosum
Bulbophyllum lineolatum
Bulbophyllum magnussonianum
Bulbophyllum microlabium
Bulbophyllum najae
Bulbophyllum palleucum
Bulbophyllum phaeoglossum
Bulbophyllum rhomboglossum
Bulbophyllum stolleanum
Bulbophyllum ustusfortiter
Bulbophyllum variculosum
Bulbophyllum versteegii
Bulbophyllum wollastonii
Bulbophyllum yumtei


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Genus Bulbophyllum section Brachypus

Bulbophyllum cerinum Schltr. cf., pseudobulbs and flowers, photo P. Jongejan, collection Royal Botanic Garden Kew, cult. P. Jongejan 3271

Genus Bulbophyllum section Brachypus

Bulbophyllum cerinum Schltr. cf., flower detail, centre of flower, oblique front view, photo P. Jongejan, collection Royal Botanic Garden Kew, cult. P. Jongejan 3271

Genus Bulbophyllum section Brachypus

Bulbophyllum magnussonianum J.J.Verm. in press, inflorescences, photo E.F. de Vogel, Leiden cult. 20081518

Genus Bulbophyllum section Brachypus

Bulbophyllum ustusfortiter J.J.Verm., flowers, view from above, photo P. Jongejan, collection Royal Botanic Garden Kew, cult. P. Jongejan 31721, (holotype)

Genus Bulbophyllum section Brachypus

Bulbophyllum variculosum J.J.Verm. cf., flower, lateral sepal removed, lateral view, photo E.F. de Vogel, Leiden cult. 930223, Jongejan 3271

Genus Bulbophyllum section Brachypus

Bulbophyllum sp. sect. Brachypus, plant habit, photo P. Jongejan, collection Royal Botanic Garden Kew, cult. P. Jongejan 240

Genus Bulbophyllum section Brachypus

Bulbophyllum variculosum J.J.Verm., drawing J.J. Vermeulen