106 ASPIDIUM 



CRESTED SHIELD FERN: 



Aspidium cristatum. 

 {Nephrodiumj Dryopteris cristata.) 



Fertile fronds quite erect^ often 3 feet high, 

 much taller than the sterile^, which are somewhat 

 reclining, pinnate; pinnae broadest at the base, 

 tapering toward the tips, the lowest pair almost tri- 

 angular, deeply pinnatifid; pinnules 6 to 10 pairs, 

 oblong, blunt, finely toothed, the lower pinnatifid- 

 lobed, and those nearest the rachis sometimes 

 separate; stipes chaffy. 



Owing to the upright stalks of the fertile fronds 

 the pinnae arrange themselves nearly in a horizon- 

 tal plane, thus appearing farther apart than those 

 of most species. 



Fruit dots as near the midvein as the margin; 

 indusium broad and conspicuous, smooth. 



Found in swampy woods from Canada to North 

 Carolina, Arkansas and Idaho. 



The variety Clintonianum has larger and broader 

 fronds, pinnae cut into 8 to l6 pairs of pinnules. 



The crested ferns often hybridize with the 

 marginal shield ferns, producing intermediate or 

 distorted fronds. 



