The fern genus Dennstaedtia (Dennstaedtiaceae) in Ecuador, - New characters, new species and a new combination

We studied the species of Dennstaedtia in Ecuador in herbaria and in the field, especially characters that are poorly represented in herbarium collections, such as growth habit, habitat, rhizome morphology, petiole morphology, and development of buds on petioles and laminae. We found that variation in these characters correlates with certain, sometimes subtle, features of lamina dissection, and sorus position, shape and size, and thus adds more significance to these than was recognized earlier. In earlier revisions some of the variability in lamina dissection was commonly considered to represent intraspecific variation, response to growth conditions, or different stages of development. As a result five species groups including a total of 18 species are now recognized in Ecuador, in contrast to eight species in earlier revisions. The groups and species are described and keyed out. Dennstaedtia auriculata, D. macrosora, D. paucirrhiza, and D. tryoniana are described as new to science, D. werckleana, based on Costaricia werckleana is a new nomenclatural combination. Dennstaedtia arcuata, D. cornuta, D. matthewsii, and D. producta, formerly reduced to synonymy, are recognized as distinct species. Four species formerly known from other countries were recorded for the first time in Ecuador during this study.