514 



RESEARCHES ON FUNGI 



from Uredineae which possessed telentospores that germinated in 

 their place of development upon their host in the manner charac- 

 teristic of normal Uredineae 

 at the present day. 



The Discharge of Basidio- 

 spores in Gymnosporan- 

 gium Juniperi-virginianae. 

 — Gymnosporangium Juni- 

 pe7'i-virgi7iianae is a heter- 

 oecious rust fungus which 

 produces its teleutospores 

 on the Red Cedar, Juni- 

 perus virginiana, and its 

 aecidiospores on the Apple 

 (species of Malus). When 

 attacking the Red Cedar, 

 the mycelium causes hyper- 

 trophy of individual leaves, 

 so that each infected leaf 

 develops into a large 

 leathery gall known as a 

 Cedar apple (Fig. 207).i 

 The galls are often several 

 centimetres in diameter and 

 there may be scores or even 

 hundreds of them present 

 upon the twigs of a single 

 tree. 



In West Virginia, U.S.A., 

 Cedar galls first become 

 apparent during June, con- 

 tinue to grow through the summer, and almost reach maturity in 

 late autumn. With the first warm weather of spring, they develop 

 numerous brownish projections which are nothing more or less than 



1 H. S. Reed and C. H. Crabill, " The Cedar Rust Disease of Apples caused by 

 Gymnosporangium Juniperi-virginianae," Virginia Agricultural Experiment Station, 

 Bull. 170, 1915, p. 18, Fig. 4. 



Fig. 207. — Qymnosporangium J uni peri-virgin- 

 ianae on Juniperus Virginiana. Mature 

 reddish-brown Cedar apples, photographed 

 April 2. The teleutospore-sori have just 

 ruptured the cortex of the gall preparatory 

 to the projection of gelatinous horns during 

 the next rain. Photographed by H. S. 

 Reed and C. H. Crabill. From Bull. No. 9 

 of the Virginia Agricultural Experiment 

 Station. Natural size. 



