Arthur and Kern: Peridermium 



405 



Abietis-canadensis Farl. on hemlock, and C. conigenum Pat., on 



pine. 



Only three of the twenty-seven species have been definitely 

 associated with telial forms. One of these, the Peridermium Pirn of 

 American authors, was found by Kellerman* to grow on Campanula 



producing Coleosporium Campamdae (Pers.) Lev.; another, Per. 

 Cerebrum Peck, has been grown by Shear and the writers on oak, 

 producing a Cronartium ; while the third, Per. elatinum, shows such 

 close morphological identity with the form in Europe proven to be- 

 long to Melampsorella Cerastii (Pers.) Schrot, that taken in connec- 

 tion with geographical distribution it seems safe to assume that the 

 American form has the same relationship as the European. Other 

 American forms have been somewhat confidently assigned to cer- 

 tain telial species, but in all cases careful study brings out so many 



Probable connection of North American species of Feridermum with 



known telial genera 



Host of 

 Peridermium 



Pycnia 



Pin us, leaves 

 Finns, bark 

 Abies 

 Tsuga 



Ephedra 

 Xbies 



Larix % 

 Picea 



Pseudotsuga 



subep. 

 subcort 



subcut. 



subcut 



subep 



Aecia 



C v 



C P 



tin bfl 



O y 



tongue-like 

 hemispherical f 



cylindrical 



7 

 8 



2 o 



< c 



^ c 



4 



I 



I 



. v 



'— u 

 0-2 



Te ial Genus 



tongue-like 



tongue-like 



Totals. 



6 



o 



25 



5 

 ii 



8 



27 



3 I 5' 



Cole os /on urn 

 Cronartium 



j Puccini a strum 

 \ Calyptospora 



j Melampsorella 

 Mela mpso ; ■ idiu m 



X 



^^Chrysomyxa 



M 



uncertainties and apparent discrepancies that it seems less likely to 

 lead to confusion if for the present such forms are described inde- 

 pendently. That cultures are absolutely demanded before the 

 Peridermium tangle can be straightened may be shown by the 



Calypt 



There 



seems to be no reason to doubt the identity of the American and 

 European rust commonly referred to the monotypic genus Calyp- 



Jour. Myc. n : 32. 1 905. 

 f An exception in case olPer.filimentosum, which is cylindrical. 

 | No Peridermium yet found in North Arreiica on Larix, but it is assumed to 

 occur. 



