14 PROCEEDINGS OF THE AMERICAN ACADEMY 



considered that the possession of this cortex was the distinguishing 

 feature of the species of his genus, although, as will be noted under 

 D. Farlowii, he did not always recognize the true cortex. It seems 

 best, therefore, to refer to Doassansia all the species of the group of 

 the Entylomata which have the sorus invested with a cortex of sterile 

 cells. 



The sori of several species referred to Doassansia show, when 

 thin sections are examined, that this cortex is not present. Such are 

 the sori of D. NiessUi, De Toni, D. Limosellce, (Kunze), Schroeter, 

 D. decijnens, Winter, and an undescribed form on Echinodorus ros- 

 tratiis, mentioned by Harkness under B. AUsmatis* These several 

 species, together with Entyloma crastophilum, Sacc, and probably 

 others, form a group intermediate between the simpler species of 

 Entijloma and those of Doassansia proper ; but the limits of this 

 group cannot be ascertained with any exactness without a careful 

 study of all the numerous forms which of late have been referred as 

 species to Entyloma. They must therefore be left unsettled in 

 position for the present. 



Among the Doassansice, as is the case among the Entylomata in 

 general, the specific distinctions are not striking. They differ slightly 

 in habit when dried, yet when fresh most of the species may be 

 distinguished at a glance by the peculiar distortion or discoloration 

 of the host plant produced by them. As a rule, the Entylomata do 

 not produce distortions, but two of the species of Doassansia cause 

 swellings of considerable size. The structure of the sorus varies 

 decidedly, and has been made in these notes the basis of generic and 

 subgeneric distinctions. The germination has been obtained wherever 

 possible, and has been found to vary in its details among the different 

 species. 



Following is given the arrangement of the species and genera. 



DOASSANSIA, Cornu. 



Spores resembling those of Entyloma both in structure and in 

 germination, collected and compacted into sori. Cortex of sterile cells 

 present. 



Subgenus I. Eudoassansia. 



Body of the sorus consisting entirely of spores, which are readily 

 separable from one another at maturity. 



* Cf. Proc. Cal. Acad. Sci., ser. 2, Vol. II. p. 231, 1889. 



