:U() THK itrsrs or nova scotia. — kraser. 



valiu'."* lie ;itl<U that liis classitieatioii has to do fundanienl- 

 ally witli ihr prosp'essive evolution of the rusts and not with 

 a(la]>rati(.iis : thus the genus Dasyspora includes species that 

 have ])r<\i»refv-e<l in their evolution to the stage where accio- 

 spores and u red iniospores have been effectively suppressed 

 from the litV cyi-le. Such a classification demands a more 

 iiitiiiiarc knowledge of the rusts and more insight into their 

 life history than the old system whi<di wns l)ased largely on 

 the structure of the teliospores. 



He also states that there arc sonu- short cut« that enable 

 one to name his collations. "'Thus, telia associated Avith 

 pycnia may be safely assumed to bcdoug to n genus in Avhich 

 aecia and uredinia are wanting, or at most so little developed 

 as to be of no taxonomic importance. In like manner ]>ycnia 

 associated with urediniii. the so-called primary uredinia, may 

 be assumed to indicate a genus in which aecia are wanting. 

 If aecia show telia arising within or about them from the 

 same mycelinm. it may >afely be assumed that no uredinia 

 belong to the life cycle. FurtJiermore it rarely or nevejr 

 hapi)ens that teliospores of the Uromyces-Pnccinia type, 

 germinating immediately on maturity, l>eloiig to genera with 

 other spore forms in the life cycle, excepting some largely 

 tropical genera. Short cuts are also available in other direc- 

 tions. All gramineous and cyjH'raceous hosts bc«,r rusts that 

 may be assumed to ])08sess all spore forms and are heteroecious. 

 Only one exception is known at present." 



In the following pages the s]jecies occurring in l*^ova Scx)tia 

 are described. The (dassification is largely that of Dietcl in 

 ''Die Xatiirlichen Ptlanzenfamilicii."' While it might })e better 

 tio follow Arthur's clas«sification, as he has made the most 

 extensive and thorough study of North American rusts, yet 

 his work has not progressed far enough to make tbat ]>ossible 

 in all cases, so for the pres.ent the clasisification that follows 

 has l>een adopted. 



