472 



FUNGOUS DISEASES OF PLANTS 



throughout that general region, and now notably destructive in 

 sections of Missouri. At any rate this species of Clitocybe is very 

 common at least from Missouri south westward, and occurs abun- 

 dantly in regions in which the root rot of apples is unknown. This 

 fungus occurs, for instance, during a favorable season in unlimited 

 quantity at Columbia, Mo., and may be found arising in large 

 clusters from the roots of hickory and other deciduous trees ; but 

 no evidence in that vicinity of its appearance in orchards has 

 come to the attention of the writer, although constant search has 

 been made for it, particularly where orchards have succeeded 



FIG. 234. CLITOCYJU-: PAR.-ISITICA: \ CLUSTER OF SPOROPHORES FROM 

 ROOT OF HICKORY 



deciduous forests. The Clitocybe is unquestionably, however, an 

 injurious fungus, and it is quite possible that the failure to attack 

 apples in certain regions is due to more favorable conditions for 

 the host. 



The fungus shown in Fig. 234 grows in very dense clusters. 

 The pilais is usually from 6 to 8 cm. in diameter, convex or 

 umbonate in form, usually beset with minute scales, varying in 

 color from mottled buff to pale ye-llowish brown. The gills are paler 

 and become mottled, noticeably decurrent at first, which charac- 

 ter is still slightly evident with age. The stipe is usually 10-16 cm. 

 in length, and up to i cm. in diameter, solid, usually curved, and 



