Verbatim text: Hinton, W. F. 1975. Systematics of the Calyptridium umbellatum complex (Portulacaceae). Brittonia 27: 197–208.
Author: Hinton, W.F.
Year: 1975
Title: Systematics of the Calyptridium umbellatum complex (Portulacaceae)
Journal: Brittonia
Volume: 27
Pages: 197–208