Monographs Details: Pleurothyrium cowaniana C.K.Allen
Authority: Maguire, Bassett. 1965. The Botany of the Guayana Highland. Mem. New York Bot. Gard. 12 (3): 1-285.
Description:Latin Diagnosis - Fruetus nitidus, viridis, fide coll., oblongus vel ellipsoideus, apice plus minusve depresse obtusatus, 25-30 X 17 mm , cupula rubra, fide coll., cyathiforma, vadosa, patenti, ad 6 mm longa et 3 mm alta, ad marginem ad 15 mm diam, stipe ad 5 mm longo, pedicello robusto, ad 2 mm longo.

Distribution and Ecology - Additional Distribution. BRITISH GUIANA. Kanuku Mts., Forest Dept. Brit. Guiana WB379 (5793) (fl. NY); Upper Mazaruni River Basin, frequent in mixed evergreen forest on talus from cliffs along NE side, Mt. Ayanganna, S. S. & C. L. Tillett 45660 (fl., fr. NY).

Discussion:A disjunct distribution, but one which may with future collections prove to be more continuous. The flowering specimens from Venezuela and British Guiana, allowing for minor variations, appear to be conspecific; however, fruitng material from other areas of the Guayana Highland sandstone may indicate the presence of two taxa.