Schistidium frahmianum (Bryopsida, Grimmiaceae), a new arctic species from Beringia

Abstract

Schistidium frahmianum Ochyra & Afonina sp. nov . is described and illustrated as a new species from Chukotka in the Russian Far East and Alaska in North America. The species belongs within subg. Canalicularia Ochyra and is closely related to S. agassizii Sull. & Lesq. but is immediately distinct in its costa which is longly excurrent as a stout terete subula and variously bistratose laminal cells at the leaf shoulders. Schistidium frahmianum is an Arctic species restricted in its occurrence to Beringia.