Hymenostylium Bridel, 1827.

Hymenostylium in California is found on calcareous seepage along creeks and roads. It is often associated with tufa deposits. The erect and unbranched stems have lanceolate leaves with pluripapillose cells, and those leaves are strongly reflexed to almost squarrose when moist. The great variation in cell morphology within a single leaf reminds one of the Weissia + Anoectangium group within the Pottiaceae, but the slightly recurved leaf margin is anomalous there. A cross-section of the stem will show thin-walled medullar cells throughout the center with no central strand.
see key to Gymnostomum Etc.

Species included:
Hymenostylium recurvirostrum (Hedwig) Dixon