146 



Mycologia 



6. Peridermium pseudo-balsameum (D. & H.) 

 Arth. & Kern 



This or closely related species of Peridermium attacks the 

 leaves of the following species of conifers: Abies grandis, A. 

 lasiocarpa, and A. nobilis. The great resemblance of these forms 

 of Peridermium to the aecial form of Calyptospora columnaris 

 (Alb. & Schw.) Kiihn. puts our determination slightly in doubt. 



The aecia are usually found sparsely in rows on the leaves of 

 the trees attacked, occurring usually only on scattering leaves, 

 so that the effect on the vitality of the tree is of little consequence. 

 No epidemics of this fungus have been noted, and it has been 

 found only on younger trees as a rule. It is frequently found 

 associated with a Melampsora on species of Vaccinium, and may 

 be the aecial form of a species of Melampsora or Calyptospora. 

 This, owing to the presence of other aecia in the vicinity where 

 collections were made, should be taken only as a suggestion for 

 future experiments. More careful studies will be made to de- 

 termine the exact relationship of these rusts on the leaves of 

 various species of Abies to Melampsora on species of Vaccinium. 



7. Peridermium conorum-picea (Russ) Arth. & Kern 



This species occurs in the west occasionally on the cones of 

 Picea engelmanni Eng., causing them to be abortive. The only 

 apparent harm done is in lessening the seed crop, but the fungus 

 has never been found in sufficient abundance to be considered a 

 serious hindrance to reforestation. The alternate form of the 

 fungus has not been found. 



8. Caeoma conigeneum Patouillard^ 



This species of Caeoma is one of the little-known forms. 

 It attacks the cones of Pinus chihuahuana Eng., rendering them 

 abortive. It occurs frequently on this host in southern Arizona, 

 but aside from lessening the seed production, apparently does 

 not injure the trees attacked. The telial form of this rust is 

 unknown. 



^Journal de Botanique 10: 386. 1896. 



