Monographs Details: Pseudatrichum
Authority: Smith, Gary L. 1971. Conspectus of the genera of Polytrichaceae. Mem. New York Bot. Gard. 21: 1-83.
Scientific Name:Pseudatrichum

Holotype: Pseudatrichum spinosissimum Reimers, Notizbl. Bot. Gart. Berlin 15:401.1941.

Pseudatrichum spinosissimum Reimers is known only from a single locality in the Chinese province of Kweichow. The only duplicate of the type collection outside of China was in Berlin, and was destroyed. Consequently, at the present time I can only speculate concerning this genus and its relationships, based on its description and its author's comments.

Reimers considered Pseudatrichum to be intermediate between Pogonatum and Atrichum, because the lamellae in this taxon occupy a portion of the leaf lamina as well as the nerve, as in some species of Pogonatum [e.g., P proliferum (Griff.) Mitt.], and the abaxial surface of the lamina bears diagonally oriented tooth groups as in Atrichum. According to my own assessment of the phylogenetic position of Atrichum and Pogonatum, any direct relationship between them is highly unlikely. The leaves of Pseudatrichwn are not bordered as in Atrichum. Reimers may have overemphasized the resemblance of the abaxial tooth groups of Pseudatrichum to those of Atrichum. H e admitted that they are "allerdings nicht so deutlich, wie bei manchen Atrichum-Arten."

Reimers discounted the possibility of relationship between Pseudatrichum and Oligotrichum, and yet there is a species of the latter in the neighboring province of Yunnan, Oligotrichum armatum Broth. (Fig. 65), which corresponds rather closely with the described features of Pseudatrichum. The leaves of the type specimen of 0. armatum (H!) do not have distinct tooth groups, but do uniformly exhibit what appear to be the "Zahnandeutungen (kurze doppelschichtige Streifen der Lamina)" of Pseudatrichum. Considering the extreme variability in the development of the abaxial lamellae within many Oligotrichum species (e.g., 0. aligerum Mitt.), it seems best to regard Pseudatrichum spinosissimum as a provisional synonym of Oligotrichum armatum Broth., until such time as material is available for comparison.