158 



evident. On a later trip (June 14, 1916) to the same vicinity the 

 trees showed scattered infections. The infected leaves appeared 

 brown and small apothecia of the fungus could be recognized. 

 The apothecia develop on the upper surface of the leaves as cir- 

 cular or elongated pustules slightly raised above the leaf surface. 

 The overlying part of the epiderm ruptures along the margin of 

 the apothecium and for some time is retained as a flap or scale as 



Fig. I. A cross section of an apothecium of Keiihia on Chamaecy parts 

 thyoides. This shows its epidermal development and marginal dehiscence with the 

 overlying flap or scale which consists of the upper half of the epidermal cell walls 

 with the thickened cuticle. The margins consist of filaments similar in form to 

 the paraphyses forming there a false excipulum. 



described for X. thujina. The exposed' apothecia are brownish 

 in color and resemble sori of uredospores. It was observed 

 that as a rule infection was confined to the lateral leaves. In 

 the majority of cases dead terminal leaves were found to be 

 infected with Lophodermium Juniperiniim Fries. This fungus 

 appeared to be more prevalent than Keithia. Ellis and Ever- 

 hart* have reported it on Chamaecy paris thyoides from Newfield, 

 New Jersey, as occurring on dead leaves. 



Weir has emphasized the importance of K. thujina as a danger- 

 ous parasite on Thuja plicata. Observations by Dr. J.J. Davis 

 in Wisconsin indicate that it is not serious, since only a limited 

 amount of leaf tissue is destroyed. The vigor of the trees is not 



* Ellis, J. B., & Evcrhart, B. M. Tue North American Pyrcnomycetcs, 718, 

 1892. 



