Schistidium deguchianum Ochyra & Bedn.-Ochyra, an endemic Andean species previously known only from its locus classicus in Urubamba Province (Cusco Region, Peru), is reported here from a second locality in the country. The species was discovered in Jauja Province (Junín Region), approximately 400 km northwest of the type locality, where it was collected in 1977 by Pirkko and Eberhard Hegewald and misidentified as S. cinclidodonteum (Müll.Hal.) B.Bremer. A morphological description and photographic documentation based on the newly identified material are provided, together with notes on its ecological preferences, taxonomic affinities, and geographical distribution. The species diversity of the genus Schistidium Bruch & Schimp. in South America is reviewed. Schistidium angustifolium (Mitt.) Herzog and S. malacophyllum Herzog are reinstated as distinct from S. amblyophyllum (Müll.Hal.) Ochyra & Hertel and S. rivulare (Brid.) Podp., respectively. Schistidium maritimum (Sm. ex R.Scott) Bruch & Schimp., S. apocarpum (Hedw.) Bruch & Schimp., S. confertum (Funck) Bruch & Schimp., S. agassizii Sull. & Lesq. and S. platyphyllum (Mitt.) H.Perss. are excluded from the moss flora of South America. In total, 20 species of Schistidium are recognized on this continent, of which 13 are well documented in the taxonomic and floristic literature, whereas seven remain known solely from their type collections. Among the accepted species, only S. rivulare (Brid.) Podp. is a widespread bipolar taxon occurring in transitional Andean habitats. The remaining species represent Gondwanan elements belonging to several chorotypes: five Andean endemics, two Afro-American tropical oreophytes, three amphiatlantic southern cool-temperate species, and two Andean taxa extending into the northern maritime Antarctic.