Pseudocrossidium R. S. Williams, 1915.
Our two species of Pseudocrossidium are very different in gross morphology. Pseudocrossidium crinitum has been called a Tortula because of the hyaline awn and rather broad leaves. It lacks the C-shaped papillae that characterize most species of Tortula or Syntrichia, and the distal portions of its leaves form an acute angle with the costa. Of greater importance is the pattern of strong recurvature of the leaf margin and the reduction of the size and density of the papillae in these near marginal areas of the leaf. The muticous P. obtusulum resembles P. crinitum in that reduction of papillar prominence near the leaf margin, and its marginal leaf curvature is revolute in that the curve completes at least a single spiral as seen in leaf cross-section.
see Keys to Barbula, Didymodon Etc.
Species included:
Pseudocrossidium crinitum (Schultz) Zander
Pseudocrossidium obtusulum (Lindberg) H. Crum & L. E. Anderson
A. Leaves with hyaline to yellowish awns; juxtalaminal, abaxial cells of the costa surface usually enlarged and yellowish-brown to orange in a pair of uniseriate rows on each side of costa .....Pseudocrossidium crinitum
A. Leaves without hyaline awns; juxtacostal, abaxial cells along distal portion of costa not differentiated .....Pseudocrossidium obtusulum