OF ARTS AND SCIENCES. 31 



II. 



CONTRIBUTIONS FROM THE CRYPTOGAMIC LABORATORY 

 OF HARVARD UNIVERSITY. 



XIX. — ON THE DEVELOPMENT OF THE SPERMOGO- 

 NIUM OF CEOMA NITENS (Schw.). 



By Herbert Maule Richards. 



Presented by W. G. Farlow, January 11, 1893. 



While the mature condition of the spermogonium of Cceoma 

 nitens has heen described and figured in more than one instance, 

 there has heen little written about its development. The general 

 impression seems to have been that the hyphse of the fungus, 

 which ramify through the tissues of the leaf, penetrate the walla of 

 the epidermal cells when spermogonia are about to be produced, 

 and that by subsequent growth the spermogonia are formed in the 

 cavities of the epidermal cells so penetrated.* It is exactly this 

 question as to whether the spermogonium actually arises within, 

 and not perhaps between, the epidermal cells, that is the subject of 

 the following remarks. It is more than a year since Pro- 

 fessor Farlow suggested to me the advisability of settling this 

 disputed point, but until the present spring I did not have a 

 chance of carrying out the suggestion. In the spring of 1891 

 I collected in the vicinity of Cambridge a considerable amount of 

 material of the spermogonia of Cceoma nitens on Rubus villosus. 

 It was gathered in the latter part of April, and was at that time 

 in very young condition, having scarcel}' begun to show itself on 

 the surface of the leaves. The material was killed in hoi picric 

 acid, and was then successively treated with the usual grades of 

 alcohol, so that it was in good condition for examination. At 

 first, free hand sections were wholly used, but afterwards sections 

 cut in paraffin with a microtome were also employed for confirm- 

 ing certain points that could only be settled by serial sections. 



* Burrill, in " The Prairie Farmer/' Vol. LVII. p. 702, 1885. 



