Hedgcock & Hunt : Coleosporium 301 



species may have a common host in the north central United 

 States, a comparison of the two species is now given : 



Coleosporium ipomoeae 



Pycnia conspicuous In single ex- 

 tended rows on chlorotic spots in 

 leaves, olivaceous-black to brownish- 

 black when old, 0.4 mm. wide by 0.7 

 mm.8 long (PI. 22, fig. 1). 



Aecia in single extended rows, flat- 

 tened rhomboidal, rupturing apically, 

 0.7 mm. high by 1.6 mm. long (PI. 

 22, fig. 1). 



Aeciospores 19 by 26 fx with walls 

 1. 5 fi thick. 



Peridial cells 22 by 42 fi with walls 

 5 fi thick. 



Coleosporium ribicola 

 Pycnia conspicuous in single short 

 rows on chlorotic spots in leaves, 

 hazel to chestnut-brown when old, 

 0.4 mm. wide by 0.7 mm.9 long (PI. 

 22, fig. 2). 



Aecia in single short rows, flat- 

 tened rhomboidal, rupturing apically, 

 1.3 mm. high by 2 mm. long (PI. 22, 

 fig. 2). 



Aeciospores 18 by 30 fi with walls 

 3.5 fi thick. 



Peridial cells 23 by 26 p with walls 

 4 fi thick. 



Coleosporium ribicola, according to our records, has been col- 

 lected as follows in the United States : 



O and I on Pinus : 



P. edulis : Colorado and New Mexico. 

 II and III on Grossularia and Ribes : 



Grossularia cynosbati (L.) Mill : Minnesota and Wisconsin. 

 G. inermis : Colorado, New Mexico, Utah, and Wyoming. 

 G. leptantha: Colorado and New Mexico. 

 G. reclinata: Colorado, Minnesota, and Wisconsin. 



G. setosa (Lindl.) Cov. & Britt : Wyoming. 

 Ribes americanum : Colorado and Wisconsin. 



R. aureum: Colorado,- New Mexico, Minnesota, South Dakota, Utah, and 

 Wyoming. 



R. coloradense : 10 Colorado, New Mexico, and Utah. 



R. inebrians (includes R. pumilum Nutt.) : Arizona, Colorado, Montana, 

 New Mexico, South Dakota, Utah, and Wyoming. 

 R. mescalerium Cov : New Mexico. 

 R. montigenum McCl : Colorado. 



R. odoratum: Colorado, Minnesota, New Mexico, and Utah. 



R. sanguineum : Minnesota. 



R. wolfii: Colorado and New Mexico. 



8 For C. ipomoeae in each case 100 measurements are given from 10 col- 

 lections, 4 on Pinus echinata, 2 on P. rigida, and 2 on P. taeda. 



9 For C. ribicola in each case 10 measurements from one collection on Pinus 

 edulis are given. 



10 Credit should be given to Professors E. Bethel and A. O. Garrett for 

 many collections of this rust from the Rocky Mountain region. 



