400 PROCEEDINGS OF THE AMERICAN ACADEMY. 



EXPLANATION OF THE PLATE. 



All figures were drawn with the aid of an Abbe camera, using a Leitz objective 

 No. 7 and ocular No. 3, reduced one fourth. 



Figs. 1-4. Stages in tlie development of the form on Phegopteris Dryopteris, 

 from Shelburne, N. H. 

 " 5-8. Similar stages as seen on Cystopteris fragilis, from Manitou, Col. 

 " 9, 10. Extreme sizes noted on Phegopteris Dryopteris, Eriksson, Fung. 



Paras. Scand. 70 h. 

 " 11-14. Immature spores on Phegoptens Dryopteris, cleared and stained, 

 showing position of germ pores. 

 15. A spore of the form on Woodsia glabella. 

 " 16. From, specimen on Ad iantum Capill us -Veneris. 



