18 
Journal of Agricultural Research voi. xxx, No. 1 
pointed out in 1907 the unusual posi¬ 
tion of the variety. Wilson G. Shelley, 
formerly in charge of the experiments 
of the United States Office of Cereal 
Investigations at the Akron Field 
Station, Akron, Colo., observed in 1910 
that Burt was a promising early va¬ 
riety and recorded in his field notebook 
that the kernels of the variety lacked 
uniformity in color. 
In 1916 one of the writers (Parker) 
observed (100) that the Burt oat had 
potential value because of its resistance 
to rust. Several strains of Burt were 
being grown at the Kansas Agricul¬ 
tural Experiment Station when he took 
charge of the crop improvement pro¬ 
ject in 1918. A special effort was 
made to obtain additional strains from 
all possible sources. Pedigreed selec¬ 
tions were made from several strains, 
and studies of the smut resistance of 
Burt and other varieties were started. 
The marked variability of the Burt 
variety, clearly indicated by the earlier 
studies of rust resistance, was observed 
to be very evident with respect to 
plant and kernel characters. 
Preliminary experiments to deter¬ 
mine the nature of the variability exist¬ 
ing in the Burt oat were initiated by the 
senior writer at the Akron (Colo.) Field 
Station in 1919, at the suggestion of 
T. R. Stanton. These experiments 
were started with the Burt oat selection, 
Cereal Investigations No. 293-6-09, 
made by Wilson G. Shelley when he 
was at the Akron Field Station. This 
selection is now named Colburt (C. I 
.No. 2019). The original plan was to 
use the plant as the unit for study. 
The kernels were spaced 6 inches apart, 
25 kernels to the row, in rows approxi¬ 
mately 12, inches apart. Approxi¬ 
mately 600 plants were produced from 
the sowing of 1,000 kernels, and of this 
number 75 were retained for the study 
of variation. These plants were 
threshed by hand in the spring of 1920. 
General notes were recorded on the 
plant characters and detailed notes 
were taken on the floret characters of 
each plant. The descriptive notes on 
floret characters may be summarized as 
follows: 
1. In color the florets of some plants 
were more variable than those of others. 
2. The florets from some plants were 
uniformly dark brown or black, while 
those from others were uniformly light 
brown. 
3. In some plants the florets were 
uniformly large, and in many cases the 
large kernels were very dark in color. 
4. The awns borne by the florets of a 
single plant varied in character. The 
twisted awn was frequently observed. 
No plants were found with all of the 
lower florets of the spikelets bearing 
awns, although many awnless plants 
were observed. 
No further study was made of this 
material. 
MORPHOLOGY OF THE OAT 
SPIKELET 
A brief discussion of the oat spikelet 
is given here to make clear the genetic 
discussion which follows. 
The spikelet is borne on the thick¬ 
ened end of the slender, drooping pedi¬ 
cel which terminates the panicle branch. 
Each spikelet usually contains two or 
more florets, though one-flowered spike- 
lets occur rarely. No oat varieties are 
known which produce one, two, or 
three florets per spikelet, exclusively. 
The lower two florets usually are per¬ 
fect, while the third, if present, often is 
staminate or imperfect. The first floret 
is the largest and contains the larger 
kernel or carvopsis. 
The two lower glumes, or empty 
glumes, are somewhat unequal, lanceo¬ 
late, acute, boat shaped, spreading, 
glabrous, membranous, and usually per¬ 
sistent. Both usually exceed the 
lemma or flowering glume in length, 
except in naked oats. 
The rachilla of axis of the spikelet 
bears all of the florets and connects 
the spikelet with its supporting pedicel. 
In some species, as Avena nuda and A. 
strigosa, the rachilla segments are elong¬ 
ated and narrowly clavate, while in 
other species, as A . sterilis , A. fatua, 
and many of their cultivated deriva¬ 
tives, the segments usually are shorter 
and more thickened. Zade (156) states 
that the greatest difference between 
wild and cultivated oat species is their 
method of separation from the pedicel. 
The floret is composed of the lemma, 
the palea, and the organs of reproduc¬ 
tion, namely, the ovary with its bifid 
style, plumose stigma, and the three 
stamens. 
The lemma or flowering glume is 
the lower of the two bracts or scales 
which form the envelope of the kernel. 
It is slightly shorter and much firmer 
in texture than the empty glume. It 
is ovate-lanceolate or boat shaped, 
with the scabrous apex bifid or entire. 
The veins of the lemma and glume 
appear as slender, riblike striations. 
In some wild forms the veins of the 
lemma extend beyond its apex as teeth 
or awn points and are used as char¬ 
acters in distinguishing species. The 
number of the nerves is variable, 
usually ranging from 7 to 11 in culti¬ 
vated varieties. The base of the 
