BOTANICAL GAZETTE. 329 



ovate-obtuse or ellipsoid 20-26/.* by 16-20//.. Oospores rather 

 small, 22-32// in diam., yellowish brown, exospore smooth. 



On Ranunculus acris and -ft. bulbosus. 



Massachusetts (Farlow), California (Harkness). Europe. 



One of the commonest species in the East, especially early in the season, 

 but certainly less common in the West, from which region I have not seen any 

 specimens, although the species is said to occur there. It covers the whole un- 

 der surface of the leaves with a dense down, and oospores are frequently found 

 in the hosts mentioned ahove. Our form is decidedly more luxuriant than 

 that found on B. Ficaria in Europe. 



21. P. Trifoliorum De Bary. 



De Bary 1. c. p. 113; Cat. Pac. Fung. p. 29. 



Conidiophores rather slender, several times dichotomous, di- 

 visions spreading and flexuous, tips acutely subulate, divergent, 

 conidia broadly elliptic, obtuse, 19-26// by 15-19//., violet colored. 

 Oospores 26-34/i in diam., thick walled, exospore dark brown, 



nearly smooth. 



On Astragalus Canadensis. 



Iowa ( Arthur), Minnesota (Farlow), California on clover (Harkness). Eu- 

 rope. 



To this species should be referred a form common in Iowa and Minnesota 

 on Astragalus Canadensis. It forms dirty-white patches on the under surface of 

 the leaves, the upper surface of which becomes more or less yellow. Our form on 

 Astragalus is more luxuriant than any of the European forms of the species which 

 I have examined, and oospores are frequently found. I have not examined 

 California specimens. In spite of their more luxuriant growth I can see no 

 specific difference either in the conidia or oospores by which one could separate 

 our plant from that of Europe. 



22. P. Cor yd a lis De Bary. 



De Bary 1. C. 107. 



Conidiophores slender, simple below, above several times 

 dichotomous, divisions flexuous. Tips slender, elongated, curved. 

 Conidia broadly 'ovate, '20-24//. by 16-20//, pale violet colored. 

 Oospores 26.5-43// in diameter, exospore brown, slightly rugose. 



On Dicenira. 



Buffalo, N. Y. (Clinton). Europe. 



This species covers the whole under surface of the Je'ave with a dirty-white 

 down, and in all speciufens which I have examined the oospores have been very 

 abundant. Mr. Clinton informs me that the host is I). Canadensis or D. CncuUa- 

 ria, and that the fungus perhaps occurs on both species. Our fungus agrees well 

 with European specimens as far as the conidiophores and conidia are concerned, 

 but the walls of the oogonia are not thick and rigid, but easily collapse, and on 

 this account the species is here inserted with the Effasce. American specimens 

 do not so well agree with the European P. affinis Kossm. as far as their conidia 

 are concerned, although the oogonia resemble those of the last named species 

 In examining a considerable number of specimens of P. Corydalis and P. affinis 



