1921] SPENCER—BRAZIL NUTS 273 
weight is the same as that of sound nuts. When the shell is 
removed the kernel presents a dull black appearance which, if the 
whole nut is affected, reminds one of a large sclerotium. A cross- 
section of the diseased kernel shows the blackened portion to consist 
of a thin layer, too-250 mu in thickness, apparently having no 
connection with the tissues beneath, which, aside from their light 
brown color and their pronounced nut odor, appear to be normal 
Fics. 1, 2.—Fig. , Diagrammatic drawings of cross and longitudinal sections 
of Brazil nut: @ and _ “loctile i in testa; 0, en osperm layer; ¢, procambium layer; 
d, medullary tissue; e, outer layer of outer seed coat; j, inner layer of outer seed coat; 
é, = tissue filling | corners of shell; /, inner “ coat; fig. 2, pycnidium with imma- 
ture spores, Pdlionidla macros pore Rh. Sp.; 
(figs. 34-36). The diseased nut meats are frequently found covered 
with various fungi, chiefly Penicillium or Aspergillus, with black 
crust under the mold. A study of microtome sections shows that 
the mycelium is in the endosperm layer, the affected cells of which 
are hypertrophied (figs. 34, 35). The cortical cells of the radicle 
immediately beneath are not parasitized, but their contents are 
markedly changed. The proteid grains are almost or quite lacking 
in the epidermal and outer layers of the normal cortex, while in 
diseased nuts there is a superabundance of small proteid grains in 
