Abstract
T. ferruginea (Schimp. ex Besch.) Ther. of Mexico is a new synonym of Didymodon fallax var. reflexus (Brid.) Zander, comb. nov. T. californica (Lesq.) Grout is morphologically similar, but can be distinguished by color reactions to strong acids and bases. Bryoerythrophyllum calcareum (Ther.) Zander, comb. nov. and B. inaequalifolium (Tayl.) Zander, comb. nov., are transfers from the genus Barbula, based partly on the different acid-base color reactions of the genera Bryoerythrophyllum and Barbula.