PLATE IS 



A. — A healthy 6-year-old apple tree contiguous to the affected tree shown in fig- 

 ure B, which appears in the background. 



B. — A 6-year-old apple tree showing pronounced symptoms of rootrot in the thin- 

 ness of the foliage and inclination of the trunk. 



C. — Xylaria polymorpha fruiting on large lateral root of a 7-year-old apple tree. 



D. — Xylaria hypoxylon developing stromata on an apple root after three months in 

 a moist chamber. 



E. — Terminal growths of trees shown in figures A and B, showing effect of rootrot 

 on annual increase in length: a, branch from the tree affected by rootrot; b, branch 

 from the healthy tree. 



(174) 



