3 
ties, tuckahoe contains so large a percentage (from 64 per cent, R. 
T. Brown, to 78.4 per cent., Department of Agriculture.) 
Quite distinct from these pectin bodies or grains— as I shall call 
them hereafter — are the hyphce of some species of fungus that are 
found in tuckahoe. In the specimens examined, the hypha^ form a 
dense mycelium at and near the surface (Figs, i, 2, 3 and 4), and 
also at all places where the white mass of tuckahoe shows the small- 
est fissures or cracks. Wherever the mass of pectin granules is 
compact and uninterrupted the hyphse are either not seen at all or 
only very sparingly; nor could I detect any within the tissue of the 
central root (Figs. 6, 7 and 8). The wood- cells of the outer "bark," 
however, contain the hyphae in great abundance, some, especially 
those nearest the surface (Figs, i and 4}, to the exclusion of the 
pectose grains. The farther we proceed toward the centre, the more 
we find the pectin grains preponderate, until the hyphse disappear 
t^early altogether. The same conditions can be observed in the in- 
tenor, where each of the numerous cracks forms a sort of bed or 
channel for the mycelium, which sends its hyphos right and left into 
the mass of granules. 
Sometimes we detect the end of a hypha attached to one of the 
grains, either superficially (Fig. 9^), or entering it (Fig. 9^), but I 
have not been able to find any spores or organs of fructification. 
It seems to me that too much stress has been laid on the occur- 
rence of a fungus in tuckahoe, and that no attention has been paid 
to the essential difference in the substance of the fungus (fungus 
cellulose), and of the granular bodies (pectose). This neglect accounts 
for the inconsistencies contained in the latest hypothesis (Smithsonian 
Report pp. 695 and 697) attempting to explain the formation of 
tuckahoe; "These spores [found in tuckahoe] have the property of 
convertmg the woody fibre of the root into their own substance;" 
frid. It \i,e,^ tuckahoe] gradually grows in this manner, appropriat- 
ing the bark of the root for its own covering, until it becomes too 
l^rge,^ during which process it forms a bark of its own, as already 
described." If the "spores" {pars yvo toto^ I presume) did trans- 
form the root into their own substance, we should not find pectose in 
so large a proportion, and the "bark'* of the tuckahoe is nothing 
^Jstinct in itself, but simply a very dense layer of mycelium either 
^Jth or without a zone of peripheral cells of the tree-root within 
^vhich the tuckahoe has been formed. 
jVhile studying this subject I could not help comparing the for- 
*^ation of tuckahoe with that secretion of the various resins and gums 
^vhich is known as resinosis and gummosis,* The gums in particular 
present many chemical and structural similarities to tuckahoe- They 
^ontain great quantities of pectose,t and many chemists think 
^nat pectose is, in fact, nothing but metaarabin.J Molil,§ Wigand,8 
*A. B. Frank, Die Krankheiten tier Tflanzen, p. 75 and p. 85. 
flfiisemann, rilanzenstoffe, Vol. i. (1SS2). p. 168. 
tW. Behrens. Hilfsbuch mikrosk. Untersuchungen (1883). P- 3^5 
M'nngshcim's/.i//riii.. Vol. iii., p. 115. 
