186 BULLETIN OF THE TTNIVEESITT OP WISCONSIN. 



Marginal leaf-cells papillose. 

 Costa percurreBt ...... F. Bavenelii, 85. 



Costa ceasing below apex ..... F. Garberi, 86. 



Leaves without a border. 

 Acute, cells densely cMorophyllose, obscurely papillose F. Bonnellii, 85. 

 Acute, almost hyaline, smooth . . . F. pauperculns, 99. 



Obtuse, cells pellucid, operculum conic . . F. obtnsifolios, 86. 

 Apiculate, operculum with acicular beak . F. osmnndoldes, 87. 



Leaves with a thick reddish border. Plants submersed, 



rigid F. rnfnlns, 84. i 



B. Fruit lateral. 



I. Leaves without a border. 



Obtuse, entire, plants 3-5 cm. high, fruit sub-terminal F. polypodioides, 88. 

 Rounded at apex, irregularly serrate, 1-2 cm. high, fruit 



sub-basal F. snb-basilaris, 88. 



Mucronate, regularly serrulate, fruit basal or sub-basal F. taxifolins,* 87. 



2. Leaves bordered by several rows of paler, often incrassate, cells. 



Leaf margin serrulate. 



Leaf cells obscure (6-9 X 6-12/;) . . F. cristatns, Wil8.,« 87. 



Leaf cells distinct (12-15 X 18-2i/i) . . . F. adiantoides,'' 88. 

 Leaves entire or slightly denticulate at the apex. 



Inferior lamina bordered, ceasing abruptly at base F. Floridanns, 83. 



Inferior lamina not bordered, tapering below . F. falcatnlns, 98. 



II. (PACHYFISSIDENS.) Leaves rigid, composed of more than 

 one layer of cells, opaque. 



Plants growing in water or very wet places . . F. gradifrons, 89. 



III. (OCTODICERAS.)' Plants aquatic, filiform, floating. 



Plants large, much branched, pedicel shorter than the 



capsule F. Jalianns, 89. 



Plants small, little branched, pedicel longer than the 



capsule F. Hallianns, 90. 



1 F. veutricosus of L. Sc J. Man. 



' See Appendix, no. 96. 



'J", decipiens De Not, L. & J. Man. 



* See Appendix, no. 97. 



• Conomitrium of MannaL 



