zu 



THE FUXGI WHICH CAUSE PLANT DISEASE 



The basidiospores are capable of infecting onlj- the appropriate 

 alternate host and that when the parts are still j^oung and 

 tender. 



An abnormal development of germ tubes instead of the usual 

 promycelium has been reported in some instances. According 

 to Lloj'd & Ridgwaj^ ^°' several crops of basidiospores are pro- 

 duced in one season. 



The various species usually make good subjects with which to 

 studj^ infection. The teliospore masses placed in water soon 

 become covered with basidiospores. Suspensions of these in water 

 applied to susceptible hosts- usually give positive results readily. 



G. juniperi-virginianse Lk. -°^' -^^' -^"'( = G. macropus) Schu. 



0. Pycnia epiphyllous. 



1. ^^cia (=Rcestelia pyrata) chiefly hypophyllous, usually in 

 annular groups, on thickened discolored spots, at first cylindric, 



0.1-0.4 mm. in diameter; 

 peridium splitting extremely 

 early, becoming fimbriate to 

 the base, strongly revolute; 

 peridial cells usually seen 

 only in side view, long and 

 narrow, 10-16 x 65-100 m, 

 becoming much curved when 

 wet, inner and side walls 

 rather sparsely rugose vnth 

 ridges extending half way 

 across the side walls; aecio- 

 spores globoid or broadly 

 eUipsoid, 16-24 x 21-31 fi, 

 wall hght chestnut-brown, 

 2-3 /i thick, finely verru- 

 cose. 



III. Telia appearing on 

 globoid or reniform galls 

 5-30 mm. or more in diam- 

 eter, evenly disposed, cylindric or cylindric-acuminate, 1.5-3 mm. 

 in diameter by 10-20 mm. long, golden-bromi ; teliospores 2-celled, 

 rhombic-oval or narrowly ellipsoid, 15-21 x 42-65 m; slightly or 



Fig. 265 



unipcri-virginianEG, aecia. 

 After Heald. 



