PINE . DISEASES 267 



inch long or smaller and only project slightly above the surface 

 of the needle. The life history is completed on the sow thistles 

 (species of Sonchus). 



A blister-rust of the needles of lodge-pole and western yellow 

 pine is caused by Peridermium montanum Arthur and Kern. 

 It is known from central Montana westward and northward. 

 The yellow pustules on the pine needles are about one-sixteenth 

 of an inch long and project only slightly above the surface of 

 the needle. The alternate weed hosts are probably the differ- 

 ent species of Arnica. 



A blister-rust of the needles of short-leaf pine is caused by 

 Peridermium intermedium Arthur and Kern and is known from 

 central Missouri and Arkansas to central North Carolina. 

 The yellow pustules on the needles are from one-sixteenth to 

 one-eighth of an inch long and project above the surface of the 

 needle about one-sixteenth of an inch. The alternate weed 

 host has not been determined. 



A conspicuous leaf blister-rust is known on loblolly, long-leaf, 

 sand, short-leaf, spruce, western yellow, pitch, pond and Cuban 

 pines. The causal fungus is Coleosporium vernonice B. and C. 

 ( = C. elephantopodis (Schw.) Thiim.) and is found from Vir- 

 ginia to Florida and westward to central Texas. The yellow 

 pustules on the needles are larger than those of the other pine 

 leaf blister-rusts. They are about one-fourth of an inch long 

 and three thirty-seconds of an inch high. The alternate weed 

 hosts of this rust are different species of ironweed and elephant's- 

 . foot (Vernonia and Elephantopus). 



A leaf blister-rust of pitch and Norway pine is caused by 

 Coleosporium solidaginis (Schw.) Thiim. and is known from 

 Massachusetts and central New York southward to central 

 North Carolina. Although the disease has been found only 

 within the above indicated area, there is the possibility of its 

 appearance on pitch and Norway pine at almost any point in 

 North America, since the stages of the causal fungus on the alter- 



