Monographs Details: Retiniphyllum truncatum Müll.Arg. var. truncatum
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 with white to pink-tinged flowers of savannas and scrub forest Territorio Federal Amazonas, Venezuela, Amazonian drainage of Colombia and Rio Igana, Brazil generally at altitudes between 100-200 m, but ascending to 1600 m on Cerro Duida, Venezuela. VENEZUELA. Supra ostium fluminis Casiquiare, Spruce 3131 (holotype); inter San Carlos et Solano, Spruce 3131; Yavita, Lichy 6; 1 km east of Maroa, Rio Guainia, Maguire, Wurdack ds Keith 41743; Caño Temi, Rio Atabapo, Maguire 29294; Santa Cruz, margen del Rio Atabapo, cerca de la desembocadura del Rio Atacavi, Foldats 3663; 10 km north of Maroa, Maguire, Wurdack & Keith 41754; Bonnetia-Byrsonima cretacea forest near Culebra Creek, Cerro Duida, Maguire, Cowan & Wureiack 29534, 29089; between Esmeralda Savanna and southeastern base of Cerro Duida, Steyermark 57818. BRAZIL. Pé da serra, Rio Igana, Pires 712. COLOMBIA. Amazonas: interior regions of trapecio between Amazon and Putumayo watersheds, Schultes 6903; Rio Caqueta, La Pedrera and vicinity, Cerro de La Pedrera, Schultes & Cabrera 17681, 17802. Amazonas-Vaupes: Rio Apaporis, Raudal de Jirijirimo, below mouth of Rio Kananari, Schultes ds Cabrera 13502, 14009, 14057, 14631, 14958. Vaupés: caatinga, Rio Negro, vicinity of Piedra de Cocui, Schultes & Cabrera 9513; Rio Piraparana, Raudal Na-hoó-gaw-he, Schultes & Cabrera 17112; Rio Piraparana (tributary of Rio Apaporis), Caño Teemeeña, Schultes & Cabrera 17230, 17473; Rio Piraparana, Cerro E-ree-eé-ko-mee-o-kee, Schultes & Cabrera 17502; Río Negro, San Felipe and vicinity, below confluence of Rio Guainia and Rio Casiquiare, Schultes, Baker & Cabrera 17989, 18023.

Discussion:Although the summit of the calyx was described by Miiller Argoviensis as truncate and entire, an examination of isotype material at NY (Spruce 3131) shows the calyx with five repand-denticulate protuberances on the summit. Other collections matching the Spruce specimen likewise show the five repand-denticulations of the calyx summit.
Distribution:Venezuela South America| Colombia South America| Brazil South America|