Structure and symmetry of species of the Asplundia group (Cyclanthaceae) having monopodial vegetative axes: Schultesphytum chorianthum, Dicranopygium sp. nov., Asplundia rigida, and Thoracocarpus bissectusv. 138No. 180–101
Wilder, George J. 1977. "Structure and symmetry of species of the Asplundia group (Cyclanthaceae) having monopodial vegetative axes: Schultesphytum chorianthum, Dicranopygium sp. nov., Asplundia rigida, and Thoracocarpus bissectus." Botanical Gazette, 138, (1) 80–101.