POLYPODIACEAE 



23 



Blechnum was discovered in Florida before the beginning 

 of the last century, and it grows also on the mainland 

 and islands of tropical America. 



9. ANCHISTEA Presl 



Coarse erect terrestrial swamp-plants. Leaves uni- 

 form, erect or arching, single or somewhat clustered on 

 the stout elongate creeping or horizontal rootstock: 

 blades pinnate, the leaflets pinnatifid. Veins united to 

 form a single series of elongate areolae next to the 

 midrib and its branches in the segments, elsewhere free. 

 Sori borne on trans- 

 verse veins form- 

 ing the outer sides 

 of the areolae. In- 

 dusia opening on 

 the side away from 

 the midrib. Con- 

 tains only the fol- 

 lowing species na- 

 tive of eastern 

 North America. 



1. A. virginica 

 (L.) Presl. Boot- 

 stock stout, usually 

 horizontal : leaves 

 erect or arching, 

 1.5 m. long or 

 less, or rarely 

 more; petioles 

 usually purple 

 and shining below, 

 green above; 

 blades lanceolate to 

 e 1 1 i p t ic-lanceolate 

 or ovate in out- 



