PLANTS OF IOWA 179 



2302. R. sayi, Schwein. Prickly Rose. 

 Common on banks and in thickets. 



2303. R, ivoodsii, Lindl. "Wood's Rose. 

 Not common, in open places. 



2304. R. humilis, Marsh. Pasture Rose. 

 Not common. 



2305. R. arkansana, Porter. Arkansas Rose. 

 Common in dry soil. 



2306. R. rubiginosa, L. Sweetbriar. 

 Introduced from Europe; in waste places. 



POMACES. APPLE FAMILY. 



Malus, Hill. 



2307. 31. coronaria, (L.) Mill. American Crab Apple. 

 Infrequent; probably the next species. 



2308. M. icensis, (Wood) Britton. Western Crab Apple. 

 Common in thickets. 



Aronia, Medic. 



2309. A. nigra, (Willd.) Britton. Black Chokeberry. 

 Very rare. 



Amelanchier, Medic. 



2310. A. canadensis, (L.) Medic. June-berry. 

 Rather common, along river bluffs. 



2311. A. botryapium, (L. F.) DC. Shad-bush. 

 On shaded rocky banks. 



2312. A. rotundifolia, (Michx.) Roem. Round-leaved June- 



berry. 

 On wooded banks and slopes. Rather common. 



2313. A. alnifolia, Nutt. Northwestern June-berry. 

 Frequent on dry slopes. 



€rat^:gus» L. 



2314. C. crus-galli, L. Cockspur Thorn. 

 Common in woods. 



2315. C. punctata, Jacq. Large-fruited Thorn. 

 Very common in thickets. 



2316. C. flabellata, (Spach.) Rydb. Fan-leaved Thorn. 

 Common in open woods. 



