336 BOTANICAL GAZETTE. 



than the others, which are rounded cylindrical, somewhat trun- 

 cate at the base, with a thickened transverse band. Oospores 

 globose, exospore brown or blackish, covered with ridges which 

 usually unite to form a net-work, some of the ridges projecting 

 into the center of the meshes. 



On Amarantus hybridus, A. retroflexus and Acriida cannabina. 



Everywhere common east of the Mississippi. Europe. 



I have examined a very large number of specimens of this species which 

 abounds on species of Amarantus, and which, with us, produces oospores abun- 

 dantly in the leaves where they are plainly visible to the naked eye, and I can 

 see absolutely no specific difference between our forms and that on A. Blitum of 

 Europe. I have compared oospores on our species of Amarantus and Acnida, and 

 they correspond precisely to those in Bahh. Fung. Eur. no. 598 on A. Blitum, and, 

 in all, the exospore is covered by ridges which unite to form an irregular net- 

 work whose meshes are considerably larger than in C. cubicus. The ends of 

 some of the ridges project into the areolae and terminate in blind ends. The 

 species is apparently much more common in America than in Europe. 



35. C. Portulacje (DC.) Lev. 



Uredo Portulacse I>C. Fl. Franc. 

 Cseoma ( Uredo) candidus S. Fung. Am, r>or. in part. 

 Cyst. Portulacse Lev. 1. c. : De Bary 1. c, 127, PL III. 

 Exs. Ravenel Fung. Am. 500. 



Conidia of two kinds, the terminal umbilicate and larger than 

 the others which are cylindrical, and without a thickened trans- 

 verse band. Oospores as in C. Bllti. 



On Portulaca oleracea. 



With the last. Europe. 



Everywhere abundant on Portulaca oleracea and scarcely to be distinguished 

 from the preceding species. The oospores are the same in both, as I am con- 

 vinced from a large number of examinations, and, although the terminal 

 conidia in one species are larger, and in the other smaller, than the rest, and 

 the transverse band is wanting in C. Pdrtulacce, according to several writers, 

 yet, from my own observations, I have not found these marks to be constant. 

 Neither is the fact that the sori are sometimes concentrically arranged in C. 

 Portulaca characteristic for the same arrangement is not unfrequently seen in 

 the form on Amarantus. 



I would return my thanks to the following botanists who have 

 kindly furnished specimens of Peronosporeu >: J. C Arthur, 

 Prof. C. E. Bessev, Prof. T. J. Burrill, Hon. G. W. Clinton, F. 

 S. Earle, J. B. Ellis, B. D; Halsted, Dr. H. W. Harkness, E. 

 W. Holway, C. H. Peck, H. W. Ravenel, A. B. Seymour, Prof. 

 V. M. Spalding, Prof. Wm. Trelease. 



Erratum. — On page 312 after Section III for Plasmatorarve read Plasmatoparoe. 



