PLANTS OF IOWA 25 



ALBUGO. 



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

 On radishes. 



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

 On portulacea. 



PERONOSPORA. 



240. P. alisnearum, DeBy. 

 On Cerastium nutans. 



241. P. australis, Speg. 



On Echinocystis lobata. 



242. P. calotheca, DeBy. 

 On Galium boreale. 



243. P. ficarioe, Tul. 



On Ranunculus repens. 



244. P. gangliformis, DeBy. 



On Lactuca ludoviciana. Lettuce mildew. 



245. P. geranii, Peck. 



On Geranium carolinianum and on G. maculatum. 



246. P. graminicola, Schroetor. 

 On Set aria viridis. 



247. P. leptosperma, DeBy. 

 On Artemisia biennis. 



248. P. halstedii, Farl. 



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

 B. cernua, Ambrosia trifida, A. artemisicefolia, Heli- 

 anthus grosse*-serratus, H. doronicoides, Silphium per- 

 foliatum, Ambrosia trifida. On Rudbeckia laciniata, 

 R. triloba. 



249. P. lophanthi, Farl. 



On Lophanthus scrophularicefolius. 



250. P. obducens, Schroeter. 

 Impatiens pallida. 



251. P. parasitica, Tul. 



On Brassica nigra, Sisymbrium canescens, Nasturtium 

 palustre, Capsella brusa-pastoris, Lepidium virgini- 

 cum. Very common in the spring on Crmiferce. 



