Hedgcock: Notes on Western Uredineae 145 



4. Peridermium coloradense (Dietel) Arth. & Kern 



This species of Peridermmm attacks the spruces, Picea engel- 

 manni Eng., Picea parry ana (Andre) Parry, and Picea sitchensis 

 (Bong.) Trautre & Mayer. On the Engelmann spruce, it is found 

 almost throughout the entire range of the species. It causes the 

 formation of dense, deciduous, leafy, witches brooms, with 

 greatly metamorphosed, stunted branches. The presence of the 

 brooms usually bring about, in a few years, the death of the 

 limbs upon which they are situated. If the limb is adjacent to 

 the trunk, its death is often followed by the entrance of the heart- 

 rotting fungus Trametes pini (Brot.) Fr. 



In the region near Anaconda, Montana, where the forest trees 

 have been killed by smelter fumes, it was noted that these witches 

 brooms are more sensitive to the fumes than the healthy portions 

 of the trees, and that they succumb first from their effects. The 

 telial form of this species of Peridermium has not been found. 



5. A/[elampsorella elatina (Alb. & Schw.) Arth. 



The aecial form of this rust {Peridermium elatinum Kunze & 

 Schmidt) attacks a number of species of Abies. It forms leafy 

 witches brooms with adherent leaves and metamorphosed 

 branches. These brooms have a stunting effect on the limbs upon 

 which they occur. Where a number of brooms occur on the 

 same tree, the whole tree is decidedly checked in its growth. The 

 following species of Abies in the national forests of the west and 

 northwest are attacked by this fungus: A. balsamea (Linn.) 

 Mill., A. concolor (Gord.) Parry, A. grandis LindL, A. lasio- 

 carpa (Hook.) Nutt., A. nobilis LindL, and A. magnifica Murr. 



According to Arthur,* the uredinial and telial forms of this 

 Peridermium occur on species of Alsine and Cerastrum. No 

 effort has been made on the part of the writer to collect specimens 

 of telia, as all collections were made too early in the season to 

 find the telia. The aecia mature in the west from early July in 

 New Mexico to the middle of August in northern Montana. The 

 same variation in the maturing of aecia was noted in case of 

 Peridermium coloradense. 



* North American Flora 7: iii, Mar. 1907. 



