Nov. 1, 1924 
A Mycorrhizal Fungus in the Roots of Legumes 
463 
entire roots which are kept submerged 
in water. The intercellular spaces 
of the discolored cells are more or less 
filled with a liquid, this giving rise to 
which are sometimes even more con¬ 
spicuous than the color, and these are 
unmistakable evidence of the presence 
of the fungus strands, which are some- 
Fig. 1.—Transverse section of a small rootlet of Trifolium pr(dense containing the mycorrhizal fungus, 
A.—Degenerating haustoria. B.—Strands of intercellular mycelium, of which about 35 may be counted 
here. C.—Endodermal cells. 
the water-soaked appearance of the times difficult to discern in longitudinal 
tissue. The cells with discolored con- sections. A cross section of an infected 
tents usually contain large, somewhat root shows more clearly the distribution 
amorphous masses of uncolored mate- of the strands from which the haustoria 
rial, the haustoria of the fungus (PI. 1), originate (fig. I). 4 Usually they occur 
4 The writer is indebted to Dr. Charles Drechsler for the drawing of all text figures. 
