EUROPE AND NORTH AMERICA. 29 



CLAVIS TO THE SPECIES HERE DESCRIBED. 

 SPHAGNUM. 



Sect. I. — Eusphagnum, Lindb. 



Branches dimorphous, part divergent, part pendent ; their 

 leaves with spiral fibres. Capsule oblong, small-mouthed. 



A. Cymbifolia. Cuticular cells fibrillose. Branch leaves cym- 



biform-concave, the apex cucullate, squamoso-scabrous at 



back. 



Branch leaves with the lateral wall of the combined 



hyaline and chlorophyllose cells covered with papillae. 



Branch leaves minutely fringed all round the margin. 



Portoricense. 

 Branch leaves not fringed. 



Chlorophyllose cells trigonous, emerging on the con- 

 cave surface of leaf. Papilloe transverse, in a 

 single series. Austini. 



Chlorophyllose cells lenticular, entirely enclosed by 

 the hyaline. Papilloe wart-like, numerous, scattered. 



papillosum. 



Branch leaves with the lateral wall of the combined hyaline 



and chlorophyllose cells smooth. cymbifolmm. 



B. Subsemnda. Branch leaves more or less secund, ovate, 



with rounded toothed points ; the margin involute in 

 the upper half. 

 Retort cells of branches large, curved outward at apex. 

 Hyaline cells of branch leaves large. tenellum. 



Retort cells of branches small, cylindric. Hyaline cells of 

 branch leaves small. 



Cuticular cells of stem in a single layer, stibsccunditm. 

 Cuticular cells of stem in 2-3 layers. laricinum. 



C. Truncata. Branch leaves oblong, the point truncate, 



strongly toothed, margin involute for all its length. 



Stem leaves very small, tongue-shaped ; branch leaves 



ovate-oblong, toothed at apex. rigidtim. 



Stem leaves truncate, many-toothed ; branch leaves 



broadly ovate, acuminate, with 6-10 teeth. 



o 



A ngstromii. 



Stem leaves very large, ovato-lanceolate, 3-toothed ; 



branch leaves ovate-oblong, 3-5 toothed. molle. 



