Porpax williamsonii (P.J.Cribb) Schuit., Y.P.Ng & H.A.Pedersen, Bot. J. Linn. Soc. 186: 201 (2018).
Homotypic Names:

Stolzia williamsonii P.J.Cribb, Kew Bull. 33: 88 (1978).
A dwarf creeping epiphytic herb. Pseudobulbs 2-leaved, narrowly long-clavate, horizontal, appearing rhizomatous, swollen below leaves only, 2-4 cm. long, 1 2 mm. diameter. Leaves thin-textured, spreading, obovate to elliptic-obovate, rounded a apex, shortly petiolate, 1-2 cm. long, 0.5-0.9 cm. broad, articulated 1 mm. above apex of pseudobulb. Inflorescence 1-flowered, much shorter than leaves peduncle up to 3 mm. long; bract ovate-elliptic, acute, 1.5 mm. long. Flower large for size of plant non-resupinate, red-brown. Dorsal sepal concave, narrowly oblong-elliptic, obtuse 8.5 mm. long, 3 mm. broad; lateral sepals obliquely ovate-elliptic, obtuse, united for basal one-third, 7-7.5 mm. long, 3 mm. broad; mentum saccate, 2-2 5 mm. long Petals oblong-elliptic, obtuse, papillose, 7 mm. long, 2 mm. broad Lip recurved, narrowly clawed, lanceolate-ligulate, acute or acuminate, 3 5 mm. long.
After Graham Williamson (1932- ), Zimbabwean dental surgeon and collector, particularly of orchids, in Zambia and Malawi. He first found and described many species and is the author of Orchids of Central Africa (1977).
Epiphyte in montane forest; 2150-2900 m.
Flowering time:
Feb - Mar
Rwanda to N. Malawi
Flora of Tropical East Africa: Orchidaceae, Part 2; Cribb, P.J. (1978). A revision of Stolzia (Orchidaceae) Kew Bulletin 33(1) Page 88.; La Croix, I. et al. (1991). Orchids of Malawi A.A. Balkema, Rotterdam Page 185.; La Croix, I. & Cribb, P.J. (1995). Orchidaceae (Part 1) Flora Zambesiaca 11(1) Page 291.
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