Two new Neotropical taxa of Radula Dumort. (Marchantiophyta: Radulaceae) with bordered leaves

Abstract

Radula pallens var. marginata and R. smithii (subg. Volutoradula) are newly described from montane forests of Venezuela and Peru, respectively. Both taxa stand out by the presence of bordered leaf lobes. The new variety differs from R. pallens var. pallens in its narrow leaf border of one row of colorless cells with bulging trigones, while R. smithii stands out by a broad, 3‒5 cell rows wide, reddish-brown border made up of evenly thick-walled cells. A broad, pigmented leaf border of evenly thick-walled cells is also found in R. ligula from Brazil and Argentina, and in R. marginata (subg. Amentuloradula), from New Zealand, but the latter two species have very different lobules and stem anatomy. A full description and illustration of the two new taxa as well as comments on morphology, taxonomy and distribution are provided.