Lectotypification of the name Stereodon nemoralis Mitt. (Plagiotheciaceae), a basionym of Plagiothecium nemorale (Mitt.) A. Jaeger

In 1859, William Mitten described Stereodon nemoralis (≡ Plagiothecium nemorale) based on the gathering of Sir J.D. Hooker from India. However, the protologue did not indicate any specific specimen or illustration. For the past 50 years, the original material (NY 913349) deposited at the NY Herbarium has been considered as the holotype. However, this assumption has since been found to be incorrect, because in the Herbarium of The Natural History Museum exists other original material of this species (BM 1030713), collected by Hooker. In addition, the specimen from NY Herbarium is in poor condition and its most important diagnostic characters are not visible. In contrast, the material from BM Herbarium is in very good condition, and therefore it is herein designated as the lectotype. Also, the paper describes the resolution of this type, a process complicated by changes that had occurred in the provisions of subsequent botanical Codes.