Bulbophyllum petrae, Fischer & Sieder & Cribb & Kiehn, 2007

Fischer, Gunter A., Sieder, Anton, Cribb, Phillip J. & Kiehn, Michael, 2007, Description of two new species and one new section of Bulbophyllum (Orchidaceae) from Madagascar, Adansonia (3) 29 (1), pp. 19-25 : 22

Bulbophyllum petrae

G.A.Fischer, Sieder & P.J.Cribb, sp. nov.

( Fig. 1 )

Affinis B. humblotii Rolfe ex Scott-Elliot (sed parum similes) sed pseudobulbis caespitosis, inflorescentia sessili uni- vel biflore, petalis integris et columna ad margines ventraliter dentes ferenti satis differt.

TYPUS. — Madagascar. Toamasina, Ambatovy , 1088 m, 18°51’17’’S, 48°19’03’’E, 9.II.2005, Fischer & Andriantiana FS 2287 (holo-, PBZT!; iso-, K!, P!, WU!).

PARATYPES. — Madagascar. Toamasina Province, Ambatovy , c. 1000 m, 6.II.2000, Sieder & Andriantiana O 00 B184 ( WU!) . — Antananarivo Province, Anjozorobe, Fischer, Knirsch & Andriantiana FS 1642 (photo, WU!) .

DESCRIPTION

Roots numerous, along the rhizome and below the pseudobulbs.Rhizome creeping,subulate to ensiform, 1.8-2.2 mm in diam., sections between pseudobulbs 4-5 mm long, rhizome scales present. Pseudobulbs close together, orbicular, 8-12 × 8-12 mm, 1-leafed. Petiole absent – leaf sessile. Leaf blade elliptic to obovate, 12-16 mm long × 5-8 mm wide, acute. Inflorescence a short raceme, 13-18 mm long, 1- or 2-flowered.Peduncle 7 mm long, Rhachis fractiflex, not thickened, 2-3 mm long. Floral bracts 1-2, acute, 3.5- 4 mm long. Flowers with white sepals with dark purple dots, whitish petals, with dark purple specks at the tips, a white lip with dark purple spots suffusing the lip entirely, white anther and white column, with dark purple specks at its base. Pedicel and ovary 2-3 mm long. Median sepal ovate 6.9 × 2.6 mm; acute, margins entire, base broadly attached; fleshy, 3-veined, glabrous. Lateral sepals obliquely ovate, 8 × 4 mm; acute, margins entire, base broadly attached; fleshy, 3-veined, glabrous. Petals ovate-spathulate, 1.8 × 2.8 mm, lower margins ciliate, thin, 1-veined, glabrous. Lip recurved at third of its length, ovate, upper surface glabrous, finely papillose beneath. Column with wings (toothlike), 4-5 mm long. Stelidia triangular, acute, with a small acute tooth along the upper margin. Anther surface papillose. Pollinia 4; ovoid, the inner 3/4 the length of the outer.

HABITAT

Epiphyte growing in wet montane forests, 1000- 1400 m.

DISTRIBUTION

Endemic in east-central Madagascar.

ETYMOLOGY

The plant is named after the first author’s wife Petra who supported the work.

CONSERVATION STATUS

Bulbophyllum petrae is only known from two localities. The first site, Anjozorobe, is under threat of logging and through slash and burn agriculture. The type site is located in the middle of a mining area which will be partly cleared within the next 10 years. Following the IUCN (2001) criteria this species must be considered as Endangered ( EN B1 a+b (iii)) .

TAXONOMIC RELATIONSHIPS

This species is morphologically totally different from any other Madagascan Bulbophyllum species. Its flower differs from any other known Bulbophyllum species in size, form and structure.

In its floral morphology it is superficially similar to B. humblotii Rolfe ex Scott-Elliot (section Humblotiorchis) but it differs in having caespitose not widely spaced pseudobulbs, its almost sessile, one- or two-flowered inflorescences, and the shape of its petals and sepals, the petals being entire not bifid, and the shape of the column and stelidia. Only the shape and the surface ornamentation of its lip is similar to B. humblotii .

Figures

FIG. 1. — Bulbophyllum petrae G.A.Fischer, Sieder & P.J.Cribb: A, habit; B, leaf; C, flower, side view; D, dorsal sepal; E, lateral sepal; F, petal; G, lip, dorsal view; H, flower from above with dorsal sepal removed; I, flower from side with dorsal sepal and nearside lateral sepal and petal removed; J, K, anther-cap, two views; L, pollinia. Fischer & Andriantiana FS2287. Drawings by Juliet Beentje. Scale bars: A, B, 10 mm; C-I, 3 mm; J, K, 1 mm; L, 0.5 mm.