Abstract
A summary of the species of Cyathea sensu strictu with pinnate to pinnate-pinnatifid fronds is presented. All species are strictly Neotropical and are found throughout the entire range of the genus in the Western Hemisphere, but most species occur in the mountainous regions of northern South America and Central America. This artificially delimited group includes the species formerly recognized as the segregate genus Cnemidaria, which form a monophyletic group within Cyathea together with some species previously not recognized as Cnemidaria. This group is characterized by a general lack of hairs, cartilaginous laminar texture, petiole scales that have white margins or that are completely white, and large sori with diameter ≥ 1 mm and 30–40 sporangia per sorus. Cnemidaria-type spores with at least three large equatorial pores dominate in this group but are neither omnipresent nor exclusive to it. The remainder of the pinnate to pinnate-pinnatifid species of Cyathea includes predominantly exindusiate species that have moderately to densely pilose laminae and relatively small sori with diameter ≤ 1 mm and ± 20 sporangia per sorus.
Twelve new combinations are made and the following three new names are proposed: Cyathea cnemidaria (= Cnemidaria tryoniana), C. glandulifera (= Cn. glandulosa), C. suprapilosa (= Cn. suprastrigosa). A key to all species of Cyathea with pinnate to pinnate-pinnatifid fronds is provided. Hybrids are not treated.