159 



impaired. Our observations of the fungus on Chamaecy parts 

 agree with those of Davis. As previously noted, the Lophoder- 

 mium appears more destructive than Keithia. It is plainly 

 possible, however, that under more favorable conditions these 

 fungi might become serious. 



The form of Keithia on Chamaecy paris differs in several points 

 from Keithia Thujina on Thuja. Specimens of the collections 

 by Davis, Weir and Orton deposited in the herbarium of the New 

 York Botanical Garden have been compared. 



Fig. 2. a-c. Keithia on Chamaecyparis Ihyoides. a, paraphyses; b, immature 

 ascus; c, matured spore and ascus; d-g, Keithia thujina; d and e, surface and sec- 

 tioned view of mature spores; /, paraphyses; g, matured ascus. 



The fungus develops in the epidermal layer in such a manner 

 that the cells are split. The portion raised above the apothecia 

 consists of the upper halves of the epidermal cell walls with the 

 thickened cuticle. Keithia Thujina on Thuja develops sub- 

 epidermally and the hyphae of the fungus are conspicuous in the 

 mesophyll of the leaf. 



The variation in the spores is the most characteristic differ- 

 ence. The spores of our form are smooth walled in contrast to 

 the pitted walls found in K. Thujina. In both forms the spores 

 are divided into two unequal cells, the distal one being much 

 smaller. The two spores occur end to end in the ascus with the 



