Monographs Details: Retiniphyllum speciosum (Spruce ex Benth.) Müll.Arg.
Authority: Maguire, Bassett. 1965. The Botany of the Guayana Highland. Mem. New York Bot. Gard. 12 (3): 1-285.
Family:Rubiaceae
Description:Distribution and Ecology - Distribution. Shrub or small tree with red or purplish flowers in caatinga sandy openings, and border of forest in drainage of Rio Negro and Amazon, Amazonas, Brazil. Arary pira, Rio Arary, regiao Rio Negro, Froes 21341; Serra de Araracoara in ditione Japurensi, Martius 3148 (type of R. rhabdocalyx); prope San Gabriel da Cachoeira, ad Rio Negro, Spruce 2340 (type of R. speciosum); caatinga proximo a Serra dos Tucanos, Rio Uaupes, Pires 864; Manaos, Rio Taruma-miry, silva ad marginem campinae arenosae, Ducke 789; caatinga circa cataractam Cajii, Rio Curicuriary, affluente Rio Negro superiore, Ducke 24020; Upper Rio Negro, Weiss d Schmidt s.n.; Serra Wabeesee, left bank Rio Vaupes below Bela Vista, between Ipanore and confluence with Rio Negro, Schultes & Pires 9139.

Discussion:Commianthus speciosus Spruce ex Benth. in Hook. Jour. Bot. 5: 234. 1853. R. rhabdocalyx M. Arg. in Martius, Fl. Bras. 6(5) : 10. 1881, type: in campestribus mentis Serra de Araracoara in ditione Japurensi, Brazil, Martius 3148 (photo of type from Mat NY). (Fig. 34, P, P'.) The isotype of R. speciosum. shows the ribbing on the calyx as in R. rhabdocalyx and the length of the corolla-lobes in proportion to that of the corolla-tube (in R. rhabdocalyx stated by M. Arg. to be 2-3 times shorter on the lobes with respect to the corolla-tube) approximates that of R. rhabdocalyx.
Distribution:Brazil South America|