Vindication of Ulota pygmaeothecia (Orthotrichaceae, Bryophyta)

Abstract

Ulota pygmaeothecia (Müll.Hal.) Kindb. and Ulota luteola (Hook.f. & Wilson) Wijk & Margad. are two epiphytic mosses from the evergreen Magellanic rainforests of southern South America. Both mosses have been considered as distinct species since their original description, with their specific status retained following the comprehensive review by Nicolajs Malta of South American Ulota (1927). Recently the synonymization of U. pygmaeothecia and U. luteola was proposed (Wang & Jia 2016), based mainly on the similarities stated in the protologues and the study of the available type specimens of U. pygmaeothecia and U. fulvella, as the type materials of U. luteola were lost in the mail. In the present paper, all available type material for names associated with these two taxa, together with additional specimens recently collected, have been studied in depth. As a result, it has been found that both mosses show important sporophytic and gametophytic differences, both qualitative and quantitative, that allow for a precise distinction between them and they are reinstated here as distinct species. The morphological features that best differentiate U. luteola and U. pygmaeothecia are discussed and illustrated with light microscope and SEM pictures. Finally, an updated and detailed description of each species is presented.