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. laridos, 104. 



. D. rubellns, 104. 



D. Baden-PoTrellii, lis. 



D. rufus, 115. 

 D. Henderson!, II4. 



D. cylindricn», 105. 

 D. Canadensis, lie. 



DITRICHUM, p. 105.1 



Dioicous. 

 Leaves slightly twisted. 



Stem leaves spreading, perichaetial leaves hardly 



sheathing D. tortile, 105. 



Stem leaves imbricate, perichaetial leaves long sheath- 

 ing D. vaginans, 106. 



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. homomallum, 107. 

 D. ambigrnnm, I04. 

 D. flexicanle, 107. » 



D. pallidnm, 107. 



D. montannm, 10$. 



D. Schimperi, 108. 

 D. glaueescens, 108. 



^ Leptotriehum Hampe, L. & J. Man. 105. 



^ Leptotrichum brevifoliwm Kindb., Mac. Cat. 46, is described as a subspecies of iy. 

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

 this key. See Appendix, no. 105. 

 3 



