Tgtt] CHAMBERLAIN—CYCAD TRUNK 99 
I am indebted to him for the suggestion in regard to their connec- 
tions. 
The growth rings, to the naked eye, appear almost as distinct 
as in dicotyls, but under the microscope they are not so conspicuous 
(figs. 19 and 20). The latter figure presents one of the most con- 
a as 
Be.- 
20 
Losey 
SOS Sor OTS 
rOlTg, © 
1 s _. 1 ee | —< f moatiure 
(t) containing starch, the xylem tracheids, 
Fics. 16, 17.—Dioon spinulosum: fig 
wood, showing thin-walled cells of the xylem 
and the small medullary rays containing starch and calcium oxalate crystals; 
transverse section showing the phloem with several thick-walled cells, xylem 
thick-walled tracheids and several of the thin-walled cells (f); x, calcium oxalate 
crystal in medullary ray; both X125. 
spicuous rays which could be found. In Dioon edule, the rings 
appear about the same to the naked eye, but under the microscope 
are quite distinct, and seem to differ considerably from those of 
D. spinulosum, as might be expected from the description given in 
