88 
W. C. Etheridge 
Atterberg (1891) classified the varieties of oats found in northern and 
western Europe mainly on the basis of differences in the prevailing num- 
ber of grains in the spikelet, and on the absolute weight of grains and 
their percentage of kernel. The form of grains was used to subdivide one 
group, while color of grains and form of panicles were employed only as 
secondary characters to distinguish varieties which were alike in physical 
properties. Atterberg's system was as follows: 
A. Spikelets so inclined to 3 grains that middle grains are usually present; single grains few. 
I. Grains containing 59-68 per cent of kernel. 
a. Grains small; 1000 grains = 25-31 gram?. 
b. Grains medium; 1000 grains = 32-38 grams. 
c. Grains large; 1000 grains = 39+ grams. 
II. Grains containing 69-73 per cent of kernel. 
a. Grains small; 1000 grains = 25-32 grams. 
b. Grains medium; 1000 grains = 33-38 grams. 
c. Grains large; 1000 grains = 39-45 grarm.. 
III. Grains containing 74-79 per cent of kernel. 
a. Grains small; 1000 grains = - 32 grams. 
b. Grains medium ; 1000 grains = 32-38 grams. 
c. Grains large; 1000 grains = 39+ grams. 
B. Spikelets commonly with 2 grains, never with 3 grains; 1 -grained spikelets numerous. 
IV. Grains containing 69-73 per cent of kernel. 
a. Grains small; 1000 grains = 25-32 grams. 
b. Grains medium; 1000 grains = 33-38 grams. 
C. Spikelets usually with 1 grain; spikelets with 2 grains often occurring. 
V. Pointed grains. 
VI. Short grains. 
VII. "Barley" grains. 
VIII. Full, plump grains. 
Under these groups and types the grains of 1C2 varieties are described. 
In order to understand and appraise Atterberg's system his descriptions 
of the above classes must first be reviewed. These are as follows: 4 
Spikelets with 2 grains. — In these the outer and inner grains differ in size and form. 
Roughly, the weight of outer grains is 1.6 times that of inner grains; they are longer, more 
pointed, and their inner side is usually somewhat flat. Inner grains are short-pointed and 
more rounded than outer grains, although their base is somewhat pointed while that of outer 
grains ends bluntly. Unlike outer grains, inner grains are never bearded 5 and the rhachilla 
is absent or reduced to a thin, hair-like appendage bearing a rudimentary third grain. 
Spikelets with 1 grain. — When inner grains fail to form, the outer ones become normal 
single grains, their inner side convex. The rhachilla is then longer, thinner, and carries 
a large membrane or rudimentary third grain. Single grains are usually smaller than outer 
grains, but like them have on their inner side the connecting point for another grain. As 
with outer grains, the bases of single grains end abruptly. 
Spikelets with 3 grains. — On the davelooment of the rudimentary flower borne by the 
inner grain the spikelet bears 3 grains, the third grain becoming in form much like the second. 
translation from the original German. 
5 Atterberg evidently worked only with Avena sativa and Avena sativa orientalis. 
