BARNES — NORTH AMERICAN MOSSES. 



189 



DIDYMODON, p. 104. 



Leaf cells throughout quadratic 

 Leaf cells below rectangular. 



Inflorescence synoicous .... 

 Inflorescence dioicous. 

 Lid conic, leaves denticulate 

 Lid rostrate. 



Basal cells thick-walled. 

 Lamina and costa long papillose 

 Lamina and costa minutely papillose 

 Basal cells thin walled. 

 Perichaetial leaves gradually narrowed 

 Perichaetial leaves abruptly attenuate 



D. luridus, 104. 



. D. rubellus, 104. 



D. Baden-Powellii, 113. 



D. rufus, 115. 

 D. Henderson!, II4. 



D. cylindricus, 105. 

 1). Canadensis, 112. 



DITRICHUM, p. 105.1 



Dioicous. 

 Leaves slightly twisted. 



Stem leaves spreading, perichastial leaves hardly 

 sheathing . . . . . . 



Stem leaves imbricate, perichcetial leaves long sheath- 



D. tortile, 105. 



ing ....... 



Leaves not twisted. 

 Plants short (1-2 cm.), not radiculose. 

 Teeth without a basilar membrane 

 Teeth with a broad basilar membrane 

 Plants long (to 10 cm.), densely radiculose. 

 Monoicous. 



Plants short (5-10 mm.). 



Teeth cylindric, legs unequal, nodose-articulate, 

 leaves spreading ..... 



Teeth cylindric, legs equal, obscurely and dis- 

 tantly articulate, leaves spreading 

 Teeth flattened, linear, trabeculate, perforate, 

 leaves secund ...... 



Plants longer (2-3 cm.), glaucous 



D. yaginans, 106. 



D. Iiomomallum, 107. 

 D. ambignum, 104. 

 D. flexicaule, 107. » 



D. pallidum, 107. 



D. montanum, 103. 



D. Schimperi, 108. 

 D. glaucescens, 108, 



1 Leptotrichum Hampe, L. & J. Man. 105. 



"^ Leptotrichum brevifolium Kindb., Mac. Cat. 46, is described as a subspecies of £. 

 flexicaule Hampe. The characters given however are not suflBcient to justify a place in 

 this key. See Appendix, no. 105. 



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