1902] BRIEFER ARTICLES 65 



tions of a number of large resin ducts were observed. The accom- 

 panying illustrations are self-explanatory.— Mel T. Cook, Ohio State 



University^ Columbus^ Ohio, 



A ROOT ROr OF APPLE TREES CAUSED BY 



THELEPHORA GALACTINA FR. 



For thirty years or more apple growers in West Virginia, Ken- 

 tucky, southern Illinois, Missouri, Arkansas, and Oklahoma, have lost 

 numerous trees from root diseases of various kinds. The trees 

 attacked were generally young trees, from three to six years old. Dur- 

 ing the last few years investigations have been carried on in several 

 states, which show that the death of apple and other fruit trees, because 

 of root disease, is due to a number of different diseases; in other 

 words, that the term *'root-rot" cannot always be applied to one dis- 

 ease. Several fungi have been associated with root rot diseases. One 

 of these is widely distributed as a parasite of trees in the states men- 

 tioned above. Apple trees set out on newly cleared ground are 

 attacked by the fungus very soon after planting. The trees show no 

 signs of disease until the year of death. Diseased trees four and five 

 years old, with their root system almost entirely destroyed, can often 

 be recognized by excessive flower and fruit production, a phenomenon 

 frequently noted when plants are much weakened by disease. Dis- 

 eased trees die very suddenly, generally in the early summer. The 

 leaves wither and fall and within a few weeks the tree is dead. Disc. 

 eased trees always occur in groups, which indicates that the fungus 

 spreads through the soil. 



The root rot disease caused by Thelephora differs from that caused 

 Dy Agartcus melleus in that no signs of disease are evident above ground 

 until the trees are dead. The fungus causing this disease has been 

 identified by Dr, E. A. Burt as Thelephora galactina Fr. The fruiting 

 t>ody consists of bright red orange leathery sheets which form on dis- 

 eased roots and around the base of the trunk. The fungus was trans- 

 ferred from oak roots to young apple trees, killing the latter within a 

 year. 



An extended account of the mode of occurrence and growth of 

 Thelephora galactina \\\\\ be published before long. — Hermann von 

 SCHRENK, Shaw School 0/ Botany, St. Louis. 



