PLATE 17 



A. — Xylaria hypoxylon fruiting at the base of a dead apple tree. 



B. — Stumps of young apple trees which have died from rootrot after having been 

 planted where old trees had died from the same cause. Note black encrustations. 

 Photographed by Dr. H. S. Reed. 



C. — Black rootrot lesions on an apple root from Cloverdale, Va. The margin be- 

 tween diseased and sound parts is sharply marked. X. hypoxylon was obtained from 

 these lesions. 



D.— lyongitudinal section of a stroma of X. polymorpha, showing perithecia em- 

 bedded in the periphery. 



E- — Conidial stromata of X. hypoxylon in petri-dish culture on Czapec agar. The 

 direction of growth is positively phototropic. 



F. — Mature stromata of X. hypoxylon from stump shown in figxu-e A, producing 

 ascospores after one month in a moist chamber. 



