GENETICS: F. M. SURFACE 
479 
As shown in figure 2, the base of the grain or callus on the wild oat 
is expanded into a sucker-like ring. This large cleavage plane permits 
the grain to separate from the outer glumes very easily when mature. 
The cultivated grain (fig. 1) possesses a narrow contracted base and the 
grain does not shatter under ordinary conditions. 
1 2 3 
FIG. 1. VENTRAL VIEW OF THE LOWER GRAIN FROM A SPIKELET OF KHERSON OATS 
SHOWING THE CULTIVATED BASE OF THE GRAIN AND THE ABSENCE OF PUBESCENCE. X 8. 
FIG. 2. VENTRAL SURFACE OF THE LOWER GRAIN FROM A SPIKELET OF WILD OATS 
SHOWING THE WILD EASE, THE PUBESCENCE ON THE PEDICEL AND THE SIDES OF THE 
GRAIN. X 8. 
FIG. 3. VENTRAL VIEW OF THE LOWER GRAIN FROM AN Fi PLANT SHOWING THE IN. 
TERMEDIATE BASE, PUBESENCE AT SIDES OF THE BASE AND ABSENCE OF PUBESENCE ON 
THE PEDICEL. X 8. 
In the Fi generation the grain is brown in color but ordinarily not 
quite so dark as the pure wild. The base of the lower^ grain in each 
spikelet is intermediate between the wild and cultivated condition (fig. 3) . 
