Preliminary results of an orchid survey of New Britain , Papua New Guinea : five new species of Bulbophyllum ( Orchidaceae )

Five new species of Bulbophyllum, originating from New Britain in the Bismarck Archipelago, Papua New Guinea, are described.


INTRODUCTION
Surveys of the orchid flora of the island of New Britain in the Bismarck Archipelago, Papua New Guinea, carried out by the second author have yielded some 1 200 living collections, possibly representing some 300 different species.These are in cultivation at the National Capital Botanical Garden in Port Moresby, Papua New Guinea, and at Leiden Botanical Gardens in The Netherlands.Although Bulbophyllum is less well represented in this collection than in similar collections from mainland Papua New Guinea, some 25 different species have flowered so far.Five of these have proven to be new to science and are described below.Bulbophyllum drepananthum J.J.Verm., de Vogel & A.Vogel, sp.nov.(section Hoplandra) -Fig. 1 A Bulbophyllo contortisepalo et B. falcifero sepalis lateralibus subacutis nec acuminatis aut caudatis differt.-Typus: LEI 20080322 (holo LAE; iso L), Papua New Guinea, West New Britain, Asengseng logging area, Upper Au River.
Median sepal spreading, elliptic-ovate, c. 10 by 5.5 mm, index 1.8; acute-apiculate, margins entire, base broadly attached; thick, glabrous.Lateral sepals as the median, but c. 10 by 6 mm, index 1.6 -1.7.Petals porrect, ± lyriform, c. 1.5 by 5 mm excluding appendages, index c.0.3; margins with 11 appendages of 3 types (type 1: a cluster of 3 at the upper and lower edge; type 2: 3 scattered in between; type 3: 2 appendages in between those of type 1 and 2), base broadly attached; thin, glabrous; appendages of type 1 ovoid, 3.5 -4 by 0.8 mm, abruptly narrowing into a stalk of 0.5 -0.7 mm long, gradually narrowing towards a caudate tip, papillose; appendages of type 2 subulate, 3.2 -3.5 by 0.1-0.2mm, gradually narrowing into a stalk 0.5 -0.8 mm long, tip acuminate to caudate; appendages of type three intermediate between type 1 and 2. Lip somewhat recurved, elliptic-oblong, c. 3.5 by 2.1 mm, index 1.6 -1.7 (all measured without flattening); obtuse, margins entire, glabrous but papillose distally; thick; adaxially concave proximally, the erect margins slightly converging then slightly diverging; with 2 narrow ridges running parallel close to the median line, furrow in between distally converting in a row of irregular pits; surface glabrous; abaxially convex and laterally extending beyond the margins, surface papillose, on the sides with a cluster of ellipsoid vesicles.Column c. 2.5 mm long, stigma oblong, with a slight swelling at its base, column foot without teeth near the tip.Stelidia porrect, triangular, c. 0.8 mm long, acute, with a denticulate upper margin, with a distinct, triangular, obtuse tooth which has the front margin folded inwards along the lower margin, and a minute tooth in front of this.Anther abaxially ± without a crest, surface ± glabrous, front margin drawn out into a truncate beak with erose margins.Pollinia 4; ovoid, without appendage, the inner c. 0.5 × as long as the outer.
Eponymy -The species is named in honour of Dr. P.A.J. Tindemans for his continuous guidance towards the realisation of the Netherlands Centre for Biodiversity Naturalis.
Colours -Leaves dark green, slightly suffused with purple.Sepals coarsely spotted with reddish purple, the white underground visible only locally.Petals white, spotted reddish purple; appendages almost black.Lip blackish purple with a touch of green along the median line, on the adaxial side.
Distribution -Papua New Guinea, New Britain.Note -Uniquely identified within the section by having 3 different types of petal appendages.It shares the adaxially coarsely rugose leaves with B. corrugatum J.J.Verm.; next to character above, it differs in having caudate, not obtuse, petal appendages.Colours -Sepals and petals pale green, distally green, proximally suffused with red.Lip cream-coloured, greenish distally, finely spotted with red.Column yellow distally.

Bulbophyllum xyphoglossum
Habitat & Ecology -Primary forest, 250 -275 m asl.Distribution -Papua New Guinea, New Britain.Note -Shares the long lip (compared to the sepals) in combination with an antrorse tooth along the lower margin of the stelidia with B. werneri Schltr., and B. fallacinum J.J.Verm.; differs from both by the distinctly convex adaxial side of the lip, and by the larger flowers (median sepal c. 46 mm long, vs 24-32 mm long).In addition, the pseudobulbs are smaller (up to 1.2 cm long vs 2-5 cm long), and the rhizome fibres markedly less persistent.Within the section, the last character is shared only with B. cheiri Lindl.
Peduncle c. 4.5 cm long, bracts 4, the longest c. 6 mm long.Floral bracts tubular at the base, c. 6 mm, acute.Flowers not opening widely.Pedicel and ovary c. 14 mm long, basal node on a c. 2 mm-long stump.