BAENE8 — NORTH AMERICAN MOSSES. 173 



b. Stem leaves entire or with isolated gaps at the tip only. 



Chlorophyllose cells on the outer face of the leaf, triangu- 

 lar in cross section. 

 Cortex plainly distinct from wood-cylinder, branch 

 leaves almost always without pores on the inner 



face S. Mendocinum, 20. 



Cortex indistinct, branch leaves with numerous rounded 



pores on the inner face S. recurvum,! 15. 



Chlorophyllose cells exposed on both faces, quadrate or trapezoidal. 

 Borders of the branch leaves involute, pores of the outer 



face very small, in the upper cell corners . S. cuspidatum, 14. 

 Borders of the branch leaves not involute, pores of the 



outer face large (6«), in 1 or 2 rows . . . S. Dusenii, I4. 

 Borders of the branch leaves not involute, pores gener- 

 ally absent S. Fitzgeraldii, 23. 



2. Branch leaves tmall, oval or long ovate . S. molluscum,- 20. 



IV. Polyclada. 

 This section has only one species . . . . S. Wulflanum, 16. 



V. Rigida. 



Chlorophyllose cells of the branch leaves spindle-shaped 

 in cross section, hyaline cells with papillae on the 

 wall bordering the chlorophyllose cells . . . S. Garberi, 18. 



Chlorophyllose cells elliptical in cross section, smooth on 



the wall bordering the chlorophyllose cells . S. compactum,^ 17. 



VI. Subsecunda. 

 A. Stem and branch leaves without pores . . S. Pylaiei,"^ 26. 



B. Branch leaves always porose. 



I. Branch leaves with few p)ores on both faces, never in uninterrupted 



rows. 



Stem leaves enlarged from base upwards, upper margins 



involute, slightly toothed .... S. Mohriauum, 15. 



^ >Si. interynedium Hoffm., L. & J. Man. 15. 



2 S. tenellum Ehrh., L. & J. Man. 20. 



3 S. rigidum Sch., L. & J. Man. 17. 



■« Including 8, sedoides Brid., L. & J. Man. 23. 



2 



