Abstract

Introduction. While revising material of South American Syntrichia for a worldwide revision of the genus, one specimen collected in Aysén (Chile) did not match the concept of any of the species known in the genus. Here we present our argument for recognising this moss as a new species and its differentiation from other closely related taxa. Methods. About 3500 specimens from South America belonging to this genus were studied with the typical anatomical and morphological methods. In addition, most of the type material of the taxa attributed to this genus in the world has been studied. Photographic images of key features of the species were obtained for the preparation of illustrations for publication. Results and conclusions. A new moss species, Syntrichia lamellaris M.T.Gallego, M.J.Cano & Larraín, is described and illustrated from Chilean Patagonia. The species is corticolous and distinguished morphologically by its stems with irregular hyalodermis, oblanceolate to obovate-lingulate leaves that are extremely fragile, with apices ending in a spinulose red mucro, plane and strongly sinuous to lacerated leaf margins, and dorsal costal surface without stereids in the upper third, but with irregularly lobed dorsal lamellae. Possible confusion with other closely related taxa is discussed.