PLANTS OF IOWA 25 



Albugo. 



238. A. Candida, (Pres.) Kuntze. 

 On radishes. 



239. A. portulacca, (DC.) Kuntze. 

 On portulacea. 



Peronospora. 



240. P. aUsnearum, DeBy. 

 On Cerastium nutans. 



241. P. australis, Speg. 



On Ecliinocystis lobata. 



242. P. calotheca, DeBy. 

 On Galium boreale. 



243. P. ficarice, Tul. 



On Ranunculus repens. 



244. P. gangliformis, DeBy. 



On Lactuca ludoviciana. Lettuce mildew. 



245. P. geranii, Peek. 



On Geranium carolinianum and on G. maculatum. 



246. P. graminicola, Schroetor. 

 On Setaria viridis. 



247. P. leptosperma, DeBy. 

 On Artemisia biennis. 



248. P. halstedii, Farl. 



On Bidens frondosa, B. chrysanthemoides, B. connata, 

 B. cernua, Ambrosia trifida, A. art emisice folia, Heli- 

 anthus grosse-serratus, H. doronicaidcs, Silphium per- 

 foliatum, Ambrosia trifida. On Rudbeckia laciniata, 

 R. triloba. 



249. P. lophanthi, Farl. 



On Lophanthus scrophidariaf 'olius. 



250. P. obducens, Schroeter. 

 Impatiens pallida. 



251. P. parasitica, Tul. 



On Brassica nigra, Sisymbrium canescens, Nasturtium 

 palustre, Capsella brusa-pastoris, Lepidium virgiui- 

 cum. Verv common in the spring on Crudfer<B. 



