Seven new species of Selaginella subg. Stachygynandrum (Selaginellaceae) from Brazil and new synonyms for the genus

Abstract

We describe seven new species of Selaginella subg. Stachygynandrum (Selaginella alstonii, Selaginella blepharodella, Selaginella crinita, Selaginella mucronata, Selaginella mucugensis, Selaginella saltuicola, and Selaginella sematophylla) from Brazil and discuss their possible affinities and conservation status. Scanning electron micrographs of stem sections, leaves, and spores are provided to illustrate the new taxa. In Selaginella alstonii and Selaginella saltuicola vegetative growth from strobilus tips is reported and discussed. Four of the new species are from the Espinhaço Mountain Range associated with Campos Rupestres (montane savannah/rocky fields) vegetation. Three of these (i.e., Selaginella blepharodella, Selaginella crinita, and Selaginella mucugensis) were collected in the northern part of the range in Chapada Diamantina, state of Bahia, while Selaginella alstonii is from the southern part of the range in the state of Minas Gerais. Selaginella mucronata is found in Atlantic Rainforest vegetation in the state of Espírito Santo, whereas Selaginella saltuicola inhabits Cerrado (tropical savannah) vegetation in the state of Mato Grosso. Selaginella sematophylla is the most widely distributed of the new species and was collected in Espírito Santo, Minas Gerais, and Rio de Janeiro states in Campos Rupestres and Atlantic Rainforest vegetation. Selaginella alstonii occurs in rocky caves, Selaginella blepharodella, Selaginella crinita, Selaginella mucugensis, and Selaginella sematophylla seem adapted to seasonally dry places, living on sandy or humid soils, Selaginella mucronata occupies humid, forest understory, and Selaginella saltuicola is adapted to wet places associated with rocks or logs in waterfalls. Of the seven new species, six are considered local endemics (except for Selaginella sematophylla) because of their restricted currently known distributions to one or two localities within a single state in Brazil. Additionally, we propose new synonymy for Selaginella palmiformis (syn. = Selaginella bahiensis subsp. manausensis, ≡ Selaginella manausensis) and Selaginella vestiens (syn. = Selaginella fragillima); the last species is endemic to Brazil, recorded in the states of Goiás and Minas Gerais. Finally, based on literature discussed and this study, we conclude that the number of well-documented Brazilian Selaginella species is 61, of which 58 are native and three introduced and naturalized. These statistics are likely to change with further work on Selaginella from Brazil.