Characterizing Asplenium achalense (Aspleniaceae), a misunderstood species of Argentine flora: morphological, palynological and distributional evidences

Abstract

Asplenium (Aspleniaceae) is taxonomically one of the most complex fern genera with about 700 species, nearly cosmopolitan in distribution. In Argentina, Asplenium constitutes the most species-rich fern genus, with 38 taxa. Among these species, the delimitation of Asplenium achalense remain poorly understood. Some authors consider A. serra as a variant of A. achalense, or even the last species has been considered as a complex of species. The finding of a population of Asplenium achalense in Yungas after three decades without observations in the wild and neither registering more recently herbarium specimens, made it possible to analyse living material and observe new diagnostic characters present in rachises and laminae scales, glandular hairs in petioles and rachises along with spore wall features, that are critical to delimitate A. achalense as a well-defined taxon, endemics of north-west to central Argentina.