Abstract
A proposal is made to recognize the following species within Cyathea corcovadensis as currently circumscribed: Cyathea corcovadensis sensu stricto, C. feeana and C. miersii. A common characteristic of the three species is a weak leaf dimorphism, which is most evident in C. miersii where it leads to a high variability of the dissection of the lamina. Cyathea corcovadensis and C. feeana are distinct from C. miersii and other Brazilian tree ferns in having entire pinnules and abruptly reduced, pinnule-like apices on the pinnae. Both species differ from each other in relative and absolute measures of pinnule size and the position of the sori. Cyathea miersii includes all material with pinnatifid pinnules and either abruptly or gradually reduced pinnae. The possibility that it may represent a hybrid complex of C. corcovadensis and/or C. feeana with the common C. atrovirens is discussed.