ILLUSTRATIONS 



PLATES. 



Page. 

 Pl.\te I. Sections of living wliite ash trees attacked by PolypornH fraxinophilns. 



Fig. 1 . — Early stage of disease. Fig. 2. — Later stage f )f decay . Frontispiece. 

 II. Fruiting bodies oi Pol i/porns fraxinophilus on white ash. Fig. 1. — 

 Fruiting body of Fohjpornx fraxinnpliUuit. Fig. 2. — Two young 

 sporophores on living asli. Fig. :>. — An nld sjiorophore on living 

 ash : 20 



III. Fig. 1. — Transection of healthy ash wood, stained with iodine. Fig. 



2. — Transection of diseased ash wood, not stained 20 



IV. Disease caused by Folijporni^ fraxinophlluH. 1. Transection of ash 



wood, showing change in wood cells caused Ijy fungus hyphse. 

 2. Transection of medullary ray from 1)rown wood layer, showing 

 how the cells become tilled with a l)rown humus compound. 3. A 

 medullary ra}% showing later stagL'. of fungus attack. 4, 5. Tran- 

 section of wood cells, showing various stages of change of wood 

 into a ))rown humus compound. 0. Starch grains from medullary 

 ray cell. ~. Starch grains from diseased Avood. 8. Transection 

 of rotted wood 20 



V. Cross section of diseased trunk of white ash kei:)t in a moist place for 



several weeks 20 



TEXT FIGl'KE. 



Fig. 1. Map shcjwing distribution of Fraxhms americana 10 



8 



