89 



Practically, however, there appears to be but one mode of 

 distribution at all common, which is the distribution of uredo- 

 spores by the wind." (54) 



I ha\-e called asparagus rust a less highly specialized para- 

 site. Evidence of this is seen in its lesser adjustment to life 

 with its host. It is definitely toxic in its effect upon the invaded 

 cells. The leaves of an infected plant soon fall. The plant thus 

 loses the power of building food for next season's growth and 

 the asparagus stock is weakened. In striking contrast to the 

 asparagus is the rust of Pyrola, the little shin-leaf of our 

 woods. Here is restraint in feeding and an almost entire absence 

 of toxic action by the rust parasite which makes it likely that 

 rusted Pyrola will long continue resident in the Wheaton Pines. 

 All through the twenty-five acres of wooded land which adjoin 

 the campus grow scattered patches of shin-leaf. The shining, 

 evergreen leaves make a pleasing contrast to the ground cover. 

 By the end of March, sometimes when the snow has barely 

 gone, another color note is added for in many of the patches 

 the under surface of each leaf is covered with an eruption of 

 orange-colored spores. A week or two later pustules of the 

 paler yellow teleutospores may, by aid of a hand lens, be 

 distinguished among the uredospores. These teleutospores 

 germinate while still on the Pyrola leaf and their secondary 

 spores carry infection to spruce trees. Scales of young cones are 

 said to be particularly susceptible. This spruce rust is well 

 known in northern forests but I have never found it here. (32) 

 The Pyrola rust apparently thrives without its alternate host. 

 It lives as a perennial in the rootstock of its perennial host and 

 each spring the abundant uredospores can infect other Pyrola 

 plants. There are many perennial rusts but our interest in this 

 one centers upon the long vegetative period of the fungus. It 

 does not fruit on the young spring leaves but comes to fruition 

 the following spring on the overwintered leaves. These wither 

 normally in May as new leaves develop and the rust whose 

 pustules have broken the under epidermis seems to make little 

 difference in the time of their withering. (52) 



Hepatica rust is companion in the spring to Pyrola rust but 

 with a different sequence. Hepatica plants are not found in 

 Norton but I have transplanted them from the Berkshire Hills 

 to our Botanic Garden. The rust came with them and each 



