Pterigynandrum sharpii H. A. Crum & L. E. Anderson, Bryologist 70: 99. 1967, based on Hylocomium splendens var. tenue Sharp, Bryologist 36: 21. 1933; Mittenothamnium sharpii (H. A. Crum & L. E. Anderson) W. R. Buck; Taxiphyllum sharpii (H. A. Crum & L. E. Anderson) H. Robinson

Plants slender, 10 cm. Stems with elongate branches, filiform, innovations uncommon. Stem leaves moderately concave, 0.3-0.7 mm wide; alar cells few, subquadrate to oblong, 10-17 × 10 µm; laminal cells 30-80 × 4-5µm; basal cells shorter, broader. Branch leaves erect to spreading, concave, 0.3-0.8 × 0.1-0.4 mm; base slightly decurrent; alar cells slightly differentiated. Inflorescences and sporophytes unknown.

Wet, shaded rock in moist montane forests, near waterfalls or in deep ravines; moderate to high elevations (500-1700 m); N.C., S.C., Tenn.

Known from about ten localities, Leptohymenium sharpii is endemic to the Southern Appalachian Mountains and is apparently rare. Although L. sharpii was originally described as a variety of Hylocomium splendens, the stems and branches lack paraphyllia. Over the past thirty years Leptohymenium sharpii has been moved from one genus to another. The occasionally sympodial innovations, decurrent leaves, and prorulate laminal cells suggest that it belongs in Leptohymenium. Finding plants with sporophytes would aid greatly in resolving generic placement of this puzzling species.

SELECTED REFERENCE Crum, H. A. and L. E. Anderson. 1967. The status of Hylocomium splendens var. tenue. Bryologist 70: 98-101.