1 1 8 FONTINALACEAE 



linear, often long and narrow; alar cells subrectangular to sub- 

 hexagonal, forming more or less distinct auricles. Dioicous; 

 capsules sessile, little exceeding the perichaetial leaves; outer peri- 

 stome teeth long, sometimes united at apex. 



All our species are submerged, some grow attached to stones 

 and sticks in swift brooks, others in ponds and sluggish streams. 

 Rarely, if ever, are they found in stagnant water. By reason 

 of the peculiarities named the genus is easy to recognize, but 

 the species are often difficult or impossible to distinguish with- 

 out authentic specimens for comparison, as there is relatively 

 very little difference in the areolation of the leaves. 



I have used to a very great extent the monograph of the 

 family by M. Jules Cardot and hereby acknowledge my indebted- 

 ness to him, although I must confess that his eyesight for spe- 

 cific distinctions seems to be considerably more acute than 

 mine. The difficulty of identifying sterile and poorly developed 

 forms is emphasized by the fact that all the older American 

 exsiccati are badly mixed. 



Key 



i — Plants very large, leafy stems triangular, 5-7 mm. in diameter; leaves 



keeled gigantea 



Plants much smaller, not evidently three-cornered; leaves concave 



but not keeled 2 



2 — Plants very slender and rather rigid; leaves oblong-lanceolate to 



narrowly lanceolate 3 



Plants much stouter; leaves broader, oblong-lanceolate to ovate 4 



3 — Stem and branch leaves markedly different; stem leaves 4-6 mm. 



long, very longly and slenderly acuminate Sullivantii 



Stem and branch leaves little different, 2-3 mm. long, much less slen- 

 derly acuminate dalecarlica 



4 — Leaves distant, loosely erect-spreading, usually plane or slightly con- 

 cave above, rather slenderly acuminate, acute or somewhat ob- 

 tuse, soft Lescurii 



Leaves less spreading, closer, concave and often cucullate above, less 

 slenderly acuminate, more broadly obtuse, more rigid . . . novae-angliae 



F. dalecarlica B. & S. "Rocky rivulets, common," Muse. 

 App. 251, Closter, Austin, Bx!; Fairy Dell, Quogue, Mrs. J. K. 

 Creevy (25425). 



F. gigantea Sull. Frequent in brooks. Not reported from 

 S. Id. Summer. 



