8 lVi/so7i — Observations on 



of age. The tubercle itself measured about six inches in 

 diameter. 



From these facts and others which are tabulated below, I 

 concluded that the seed usually germinated on quite young 

 roots ; but that it did not send up a flowering shoot until per- 

 haps its fourth or fifth year of existence. 



The subjoined table shows the size of some tubercles, and 



the corresponding age of the oak root on which they were 

 parasitic : 



Age of Oak Root Diameter of 



in years. tubercle. 



3 I inch. 



5 2 inches. 



5 3 inches. 



5 2)% inches. 



6 1 3^ in. X I in. 



6 2^ inches. 



6 3)^ inches. 



7 2 inches. 



7 2% inches. 



8 2^ inches. 



8 3 inches. 



9 4 inches. 



lo 4 inches. 



II 6 inches. 



VII. Relationship between Conopholis and its Host. 



The flowering shoots of C. avici'icana are found above 

 ground usually some distance from the oak and often forming 

 almost a semi-circle of growth around it. Sometimes above 

 ground, too, are found the tubercles from which the stalks 

 proceed. This was particularly true at Gallitzen, Pa., as 

 observed by Professor Macfarlane. But it is only by digging 

 below the ground that any idea can be had of the huge ex- 

 crescences made by the parasite and the roots of the oak. 

 Three of these are figured on Plate I, which is a photograph 

 of a small portion of the underground material dug up at 

 Gallitzen, Pa., June, 1896. Younger stages are drawn on 

 Plate VI, iMgs. I, 2, 3 and 4. 



