1906] CHAMBERLAIN—OVULE OF DIOON 331 
judging from the caliber of the micropyle, must be quite large, although 
it was not observed directly. Early in November the various tissues 
of the ovule are recognizable, and early in December the layers of 
the integument are almost as distinct as in the following March, 
although the cells of the stony layer have not begun to thicken, and 
microtome sections of the entire ovule can still be cut. The general 
topography of the ovule, as it appears later in December, is shown 
in fig. zo. In this figure the endosperm and fleshy tissues are dotted, 
the stony layer is more deeply shaded, and vascular bundles are 
represented by dark lines. The integument conists of three layers, 
7 
Fic. 7.—Ovule photographed from above; the eosin has spread and exaggerated 
the size of the outer bundles (0). X2. 
1G. 8.—Inner vascular system of ovule, treated with eosin and photographed 
after the endosperm and part of the inner fleshy layer had been removed: 7, bundles 
of inner vascular system; m, micropyle; 0, bundle of outer vascular system; , basal 
papilla; s, Stony layer. X2. 
PYG gw T rarrcuras section of ovule treated with eosin: e, endosperm; #, bundle 
of inner vascular system; m, inner fleshy layer of integument and fused portion of 
hucellus; 0, bundle of outer vascular system; s, stony layer. X2. 
an outer and an inner fleshy layer, with a stony layer between them. 
Only a small portion of the nucellus is free from the integument. 
The fleshy layers of the integument are comparatively simple in 
structure. 
The outer fleshy layer —The outer layer at the stage shown in jig. 
17 is not sharply marked off from the stony layer. These two layers 
