OBSERVATIONS ON FOREST TREE RUSTS 
halsamea, It is found that the spore measurements vary to as great an 
extent as_^i9 ii. It was also found that the spores of the above five 
species bore a similarity in the length and shape of the beaks, these 
Fig. 2. Uredinopsis pteridis. U stcige o( Fteridium aquilinum pubescens. Note 
the coiled spore masses. 
varying in length from 3-10 fx to 12-26 fx with almost similar spore 
markings. The other two remaining species of Uredinopsis, U. 
pteridis and U. copelandi, both have spores with short stout beaks 
