74 MISSOURI BOTANICAL GARDEN BULLETIN 



its having been known for more than a century, so little is 

 understood concerning its origin and growth. 



One of the first, if not the first, description of the tuckahoe 

 was given by Dr. MacBride of South Carolina lie discussed 

 the specimen under the name Lycoperdon solid urn, which had 

 been given to it by Clayton in 1762, under the impression that 

 it was related to the common puff-ball. MacBride states that 

 the growth originates between the wood and bark of living 

 roots; that it gradually detaches the bark while it spreads 

 around the wood and converts it- into a substance similar to 

 itself. Various other observers have noted the association of 

 Pachyma with the roots of trees. One writer states that "in 

 almost every case I have observed that they have been plainly 

 attached to a root of another growth. This root is usually 

 about y 2 " t° :1 1 ' n diameter, outside the tuber frequently 

 larger; sometimes runs directly through the center of it, 

 sometimes nearer one side than the other. This root is always 

 free from hark inside the tuber and is often diminished to a 

 slender stalk or single fiber and is sometimes imperceptible, 

 having the appearance of being eaten away more or less or 

 entirely in the process of formation." In a description of 

 the discovery of several masses of Pachyma from Georgia it 

 is stated that "this growth had taken place from the roots of 

 pines as was evident from some having just commenced grow- 

 ing, the pine root extending through and reaching out at each 

 side. Others were developed to considerable size, showing no 

 appearance of any root in them, or any bark of the pine on the 

 outside as was the case with the smaller ones. I think the 

 whole root for 2" or more is changed into this substance, from 

 the fact that some of the roots extend entirely through it, some 

 of them being smaller inside and larger outside." Indeed, 

 early investigators held that the Pachyma was in the main 

 only an altered state of the root of a tree, the alteration being 

 due to the presence of some fungous disease. While there can 

 be no question that Pachyma is frequently associated with the 

 roots of trees, there is no evidence to indicate that this is in- 

 variably the case or that the fungus is in any sense parasitic 

 upon the roots of higher plants. The association would seem 

 to be purely accidental and is of course the thing to be ex- 

 pected from an underground growth of this character. 



In general, it may be stated that the structure of the 

 fungus is similar to that of other sclerotia, being made up of 

 a compact mass of threads, having a rough, dark-colored ex- 

 terior more or less resembling the bark of some trees. No 

 spores or reproductive bodies of any sort have ever been dis- 



