Porpax christopheri (P.J.Cribb) Schuit., Y.P.Ng & H.A.Pedersen, Bot. J. Linn. Soc. 186: 199 (2018).
Homotypic Names:
Stolzia christopheri P.J.Cribb, Kew Bull. 36: 639 (1981).
Description:
A dwarf creeping epiphytic herb. Pseudobulbs proximal on a creeping rhizome, globose, slightly dorsiventrally flattened, up to 1.3 X 0-8 cm, tightly covered with scarious sheaths when young, 1- or 2-leaved at apex. Leaves erect or suberect, subcoriaceous, oblong to oblanceolate, obtuse, up to 8 X 1.5 cm, with a slender sulcate petiole up to 1-2 cm long. Inflorescence basal, up to 1 cm long, I-flowered; bract longer than pedicel and ovary, ovate, acuminate, 5 mm long. Flower large for the genus, fleshy, inflated, ellipsoidal, dark maroon. Sepals united for basal three-quarters, subacute to apiculate at free apices, 1.1X 0-5 cm, bearing long white hairs on inner surface. Petals lanceolate, acute, with incurved margins, 6 X 2 5 cm, with long white hairs on inner surface and margins. Lip fleshy, conduplicate, entire, ovate-elliptic, rounded at apex, minutely papillose, 3-5 X 2 mm, basally sulcate in centre. Column short, 0.7 mm long, with an erose apex; foot 1.5 mm long, forming an obscure chin-like mentum with the lateral sepals; anther cap papillose; pollinia 8, 4 large and 4 slightly smaller.
Etymology:
The species is named after Dr Christopher Grey-Wilson who collected the type specimen.
Habitat:
It was found growing on vertical tree trunks and horizontal boughs on trees growing over a stream at about 1800—1900 m at Mufindi. This area on the south-facing escarpment of the Southern Highlands is well forested in parts although much of the forest on the higher slopes has been replaced by tea plantations and native cultivation. The type specimen flowered in cultivation at Kew in January 1981.
Notes:
Porpax christopheri is an extraordinary orchid, for it is the only species in the genus which has a basal rather than a terminal inflorescence. Its large inflated flower is also quite distinctive, for it opens only by a small operculum at the apex and the sepals and petals are clothed inside with very long white hairs which somewhat resemble fungal hyphae. These hairs are also reminiscent of those on the lip of Polystachya pubescens (Lindl.) Rchb. f.
Cultivation:
As given for the genus, cold growing epiphyte.
Distribution:
SW. Tanzania
References:
A New Species of Stolzia (Orchidaceae) from Tanzania, Kew Bulletin, Vol. 36, No. 3 (1981), pp. 639-641; Flora of Tropical East Africa Orchidaceae Part 2 Cribb 1984
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