Type. Shrub 0.1-0.3 m, flowers yellow, frequent along lower escarpment face of Sarven-tepui, Chimanta Massif, Edo. Bolivar, Venezuela, alt. 1900-2050 m, 13 Jan 1953, John J. Wurdack 34108 (holotype U S 2342483). Paratype. VENEZUELA, Edo. Bolivar. Chimanta Massif: Central Section, upper falls of Rio Tirica above Summit Camp, alt. 1940-1950 m, Steyermark ds Wurdack 521.
In the typical subspecies, known only from Cerro Yavi, the hypanthium is moderately and evenly strigose and only three primary leaf veins are evident. The Chimanta population has the hypanthium sparsely strigulose on the apical 1/4 and glabrous (or very sparsely strigulose at the extreme base) otherwise; the fourth and fifth (inframarginal) primary leaf nerves are faintly developed. The paratype of C. phelpsiae has ovate leaves like those of the Chimanta collections, rather than the lanceolate to oblong-lanceolate leaves of the Yavi holotype. Probably the closest relative of C. phelpsiae is C. thymifolia Tr.; that Colombian species has calyx lobes 1.5 X 1.5-2 mm, while the Venezuelan relative has calyx lobes 2.5-3 m m long and 1.5-2 times as long as broad. The interpretation of C. thymifolia is based upon the original description, rather than any type collection study. The material referred to C. thymifolia includes Grant 9651, Apolinar 584, and Dawe 320; these collections differ from C. alpina Naud. in the glandtipped cauline hairs and the hypanthium essentially lacking resinous glands.
From the present collections, I can see no reason for differentiating C. citrina Gleason from C. anisandra Naud., Gleason's distinctions having been blurred by new material. C. anisandra is known from Roraima, Auyan-tepui, and Yutaje (Maguire & Maguire 35322) in the Guayana Highland, and (with completely eglandular hairs) the Sierra Perija in Colombia (Cuatrecasas d Romero Castaneda 25164).