DESCRIPTIVE MANUAL 



PTERIDOPHYTA, FERNS AND THEIR ALLIES. 



This group of plants, sometimes called vascular cryptogams, is 

 represented in our flora by the maidenhair fern, brake, spleenwort, 

 shield fern, etc. The Boston fern is frequently cultivated. 



Fig. i. 



Common Horsetail (Equisetum arvense). Roadsides, fields, common 

 everywhere in Iowa. 

 (Photographed by Colburn.) 



Fig. 1-A. Distribution of Common Horsetail. 



