A Classification of the Varieties of Cultivated Oats 121 
varieties; and, while they may. be used in general description, such 
characters are not in themselves a reliable means of distinction. 
PUBESCENCE AT THE NODES 
Another character of the culm having a minor descriptive value is the 
pubescence slightly above and below the nodes. This differs among 
varieties, but not sufficiently to warrant an important use in classifica- 
tion (fig. 19). 
THE ROOTS 
There are no varietal differences of roots that may be 
used in classification. Schneider (1912), from studies of 
the vegetative characters of oats, believes the ratio of the 
root mass to that of the parts above ground is a varietal 
characteristic and is constant under different environments; 
but his plants were grown in pots, and hence were not 
exposed to extreme conditions. Bunger (1906), on the 
other hand, found under field conditions that the mass 
ratios of all parts of the oats plant were directly related 
to soil fertility and soil moisture. In the present study 
no structural differences have been found among the roots 
of different varieties, and, although often there were marked 
differences in root mass, such differences were found also 
within the same variety, being merely an expression of a 
more vigorous growth. 
19. SEC- 
TIONS OF OATS 
STEM SHOW- 
ING (a) stems 
hairy at the 
nodes and 
(b) stems 
glabrous at 
the nodes 
HABIT OF PLANT IN EARLY GROWTH 
The habit of the culms in early growth is one of the most important 
characters of the oats plant. It has not been considered by previous 
investigators, probably because the varieties classified displayed only 
the common erect habit. Among varieties of the present classification, 
however, there are three distinct forms in early growth — spreading, semi- 
spreading, and erect (fig. 20). The young plants of the first type are 
prostrate in early growth and send out spreading tillers, which later become 
erect from a somewhat decumbent base. Those of the semi-spreading 
type are less prostrate than those of the spreading type, and between 
the time of shooting and that of heading their tillers slant rather than 
