204 A MANUAL Ol" MOSSES 



gonial branches elongate and acute : slender to very robust : 

 stems sharply 3-angled to round, much branched ; leaves of 

 one form, 3-seriate, otherwise as for the family, ecostate ; 

 perichcetial leaves larger, almost enclosing capsule, broadly 

 obovate, obtuse, lacerate when old : vaginule and seta rudi- 

 mentary ; capsule oval to ovate, mostly delicate ; peristome 

 double, inner and outer of same length, teeth 16, linear-lanceo- 

 late, orange to brownish, plane, papillose, mostly apically 

 united in pairs, the divisural zigzag, articulations prominent, 

 the trabeculse projecting both ventrally and laterally; seg- 

 ments 16, filiform, united by lateral processes into a plaited 

 cone, rarely free and appendiculate ; spores irregular in size, 

 mostly green, almost smooth ; lid conic, calyptra reaching but 

 little below the operculum, the base lacerate when old. 



A genus of about 50 species ; about 30 occurring in North 

 America; at least five occurring in our region. 



Key to the Species. 



a. Stem-leaves carinate. 1. F. antipyrctica. 



a. Stem-leaves not carinate. b. 



b. Alar leaf-cells distinctly differentiated. 



d. 

 b. Alar leaf-cells little or not at all differentiated. 



c. 

 c. Perichaetial leaves with rounded and mostly lacerate apex. 



4. F. dclmarci. 

 c. Perichcetial leaves with an entire abruptly pointed apex. 



5. F. dalecarlica. 

 d. Leaf-cells rhombic-hexagonal, not more than 1:6. 



e. 



d. Leaf-cells elongate-linear, about 1:7-30. 



f. 

 e. Branches remote, spreading at almost right angles; leaves not 



dimorphic. 6. F. novac-angliae. 



e. Branches close, erect-spreading; vernal leaves replaced by summer 

 leaves of a different form. 2. F. bifonnis. 



f. Alar leaf-cells much differentiated; leaf-apex entire. 



3. F. sullivantii. 



f. Alar leaf-cells but moderately inflated; leaf-apex mostly plain- 

 ly toothed. 7. F. lescurii. 



1. Fontinalis antipyretica variety gigantea Sullivant. 



(Fontinalis gigantea Sullivant). 



Floating, long, dark, brownish-green or golden green : 

 stems denuded below, slender, up to sometimes 6 or 8 dm. 

 long, irregularly divided ; the branches turgidly three-cor- 

 nered and sometimes 2 or 3 dm. long; leaves deeply concave, 

 carinate, up to 6-8 mm. long, 3-4 mm. wide, broadly ovate or 

 lance-ovate, entire, acute, plane-margined ; median leaf-cells 

 about 8-15:1, linear-rhomboid and more or less vermicular, 

 the apical and basal shorter and wider, the alar sub-rectangu- 

 lar and inflated ; perichsetial leaves closely imbricated, the 



