15 
once pinnate ; pinnae crowded, pinnatifld ; pinnules nearly entire ; 
stipe jointed at about one-half inch from the base. Not uncom- 
mon on exposed rocks. Very variable in northern sections. Mid- 
dle of August. Europe and Asia. 
157. W. alpina (Bolt) S. F. Gray. (W. kyperborea. ) Fronds 
2-6 inches long, laminae greensand nearly smooth on both sides, 
pinnate ; the pinna? sparsely pinnately lobed ; stipe jointed. Moun- 
tain ravines of northern Vermont ; Mt, Mansfiield ; Mt. Willoughby 
Pringle. August. Europe. 
Appears in Vermont plants to intergrade with the preceding. 
Eggleston. 
158. W. glabella E. Br. Smooth Woodsia Fronds 2-5 inch- 
es long ; laminae linear, smooth, pinnate, the pinnae very obtuse 
and few lobed ; lower pinnae remote ; stipe jointed. Mt. Willough- 
by and Mt, Mansfield ; Bakersfield ledge, Vt., Pringle Gorham, N. 
H., Deane. “On moist, mossy rocks, mountains of Northern New 
England, etc.” — Prof. Eceton. Early August. Europe. 
Illustrated in Gray’s Manual. 
162. W. obtusa (Spring.) Torr. Obtuse Woodsia. Fronds 
10-18 inches long ; laminae lance-oblong, bipinnate. nearly smooth ; 
pinnae triangular ovate, obtuse, the lowermost pairs remote ; pin- 
nules crowded, obtuse, incised, several sori to each division ; in- 
dusium split into several lobes ; stipe not jointed. Not common, 
especially in Ehode Island and eastern Massachusetts, and often 
disappearing in August. North America July. 
Illustrated by Meehan, Series n, Voi’ 1. 
Tribe X, DICKSONLU). 
DICKSONIA L’Her. 
Indusium cup-shaped, adnate to the margin of the frond and en- 
closing the receptacle bearing the sorns. In the United 
States but one species, 
