THE WOOD FERNS. 141 



swamp, though it may be found along streams, in moist 

 thickets and occasionally in the open ground. 



A form principally distinguished by its much larger 

 and broader fronds is known as the variety Clintonianum. 

 It is found in rich wet woods in America but has not 

 been reported from the Old World. It may sometimes 

 be mistaken for Goldieanum but is easily distinguished 

 by its broad triangular lower pinnae. 



Mr. Davenport has recently described a curious plant 

 with characteristics intermediate between this species and 

 marginale which he calls A. cristatum X marginale. He 

 considers it a hybrid and describes it as having the upper 

 part of the frond like 'marginale and the lower third like 

 cristatum, with veining and texture like the latter. The 

 rootstock is erect and the frond is very prone to vary and 

 to produce abortive and misshapen fronds. The sori are 

 borne near the margin of the pinnules and the indusium 

 is convex as in marginale. Thus far it has been found 

 in various places in all the New England States and 

 in New Jersey. 



m Clintonianum. Middle pinna. 



Aspidium Eoottii. 



In appearance Aspidium Boottii stands half way be- 

 tween the crested and the spinulose shield ferns and is 

 sometimes thought to be a hybrid between them. It has 



