Strangulate Orthotrichum Moss

Orthotrichum strangulatum Beauv
Prodr. Aeth. 81. 1805.
Orthotrichum parvulum Mitt. Jour. Linn. Soc. 8: 25. 1864. Orthotrichum Porteri Sull. & Lesq.; Aust. Musci App. 28. 1870. Orthotrichum Peckii Sull. & Lesq.; Aust. Musci App. 29. 1870. Orthotrichum cupulatum var. Peckii Sull. Ic. Muse. Suppl. 61. 1874. Orthotrichum cupulatum var. Porteri Sull. Ic. Muse. Suppl. 61. 1874. Orthotrichum cupulatum var. parvulum Sull. Ic. Muse. Suppl. 61. 1874.
Plants in dense, thin mats, very dark, almost black except the young tips, 1 cm. or less in height; upper and perichaetial leaves often slenderly acute but otherwise hardly to be distinguished from those of 0. anomalum; some lower leaves nearly plane-margined and obtuse, often bistratose on the margins above; costa occasionally percurrent; basal leaf-cells rather shorter than in O. anomalum, short-rectangular to quadrate, the upper papillose with low, simple papillae; autoicous; seta about 0.5 mm. long; capsules about 1.5 mm. long, tapering to the seta, typically subcylindric and about half-emergent when dry, oblong-cylindric and often nearly immersed when moist, 8-ribbed; calyptra hairy with papillose hairs; exothecial cells differentiated along the ribs ; stomata immersed, about the middle of the capsule ; annulus present ; operculum conic-rostellate ; peristome usually single, the teeth 16, more or less paired, erect to spreading, papillose, the papillae often joined in vague, irregular, branched ridges; spores maturing in spring.
Type locality: Pennsylvania {Muhlenberg).
Distribution: On limestone; Vermont and Pennsylvania, west to Minnesota and Utah, south to Missouri, Tennessee, and Kentucky.