572 THE ORTHOTRICHE^ OF YORKSHIRE. \_October, 



subject to variation, it must sometimes be difficult to distinguish 

 tbem. I am imperfectly acquainted with 0. pumilum, but speci- 

 mens from Bruch have shorter, more acute leaves, larger areolae, 

 and are not papillose. 



7. O. obtusifolium, Schrad. Dioicous; leaves ovate-obtuse, 

 concave, with plane margins, imbricated, gemmiparous. Barren. 

 Ash-trce near York, Sept. 1855, Mr. Wilson. 



Leaves short, obtuse; nerve not reaching the apex, areolae 

 large, quadrate, bearing coarse papillae. No other species has 

 the margins plane. 



(O. Rogeri, Brid,, has narrow, ligulate leaves, lax and incurved 

 when dry, carinate ; it is monoicous) . 



8. O. Sprucei, Mont. Leaves lurid-green, elliptic-spathulate, 

 apiculate ; nerve weak ; areolae large ; cilia 8 ; calyptra cam- 

 panulate, naked. By streams. May, June. Banks of the Swale, 

 Codbeck, Ouse, Wharfs, etc. 



Stems much shorter than those of 0. rivulare ; leaves convex, 

 broader in the upper half, imbricated when dry ; areolae two or 

 three times as large. Whereas in 0. rivulare the leaves are spread- 

 ing and ligulate, broader in the^lower half, carinate, with a strong 

 nerve, margins more revolute ; areolae very minute ; apex obtuse, 

 subserrulate. 



9. 0. rivulare, Turner. Stems elongated, prostrate; leaves 

 lurid, spreading, flaccid, ovate-ligulate obtuse; nerve strong; 

 areolae minute; cilia 16, long, arcuate; calyptra campanulate, 

 dull-green, naked. Stones by streams. May, June. Found in com- 

 pany with the former. Dalton, Kilvington, Arusley, Thirsk, etc. 



II. Affin^. Capsule of thin texture, leptodermous ; ribs about half 

 as broad as ilie interspaces, sometimes confined to the upper lialf of 

 the capsule* Lid with a long beak. Spores large, green. One or 

 two inches high. 



10. 0. affine, Schrad. Leaves of coarse texture, lax and un- 

 dulated when dry, oblong- lanceolate, acumiuulate; capsule 

 narrow, tapering into the pedicel, pale; cilia 8, strong; calyptra 

 conic- campanulate, pale-green, slightly hairy. Near the roots 

 of trees, walls, etc. June, July. Capsules thin and furrowed 

 when old, slightly contracted below the mouth. Lid long, with 

 a scarlet border. 



/3. rigiduni. Leaves more acuminate, rigid, erect when dry ; 



