COMMON VETCH AND ITS VARIETIES 
11 
percentage of hard seed is at no time high except in the case of 
Vicia sativa macrocarpa. In tests at Corvallis, Oreg., the hard seed 
of this variety has ranged for various seasons from 60 to 99 per cent 
three months after harvest and diminished about 15 per cent during 
each subsequent year. The accompanying diagram (fig. 3) shows the 
rate of decrease in the percentage of hard seed in this variety for a 
period of five years. In all other varieties of common vetch the 
proportion of hard seed is small. In order to determine the relation 
of hard seed to age, tests were made each three months after harvest, 
as given in Table 3. These results show no change in the first 18 
months. Table 4 shows that Oregon vetch seed germinates promptly 
and under favorable conditions more than 90 per cent germinates 
in the first three days. The temperature of the germinating chamber 
determines to some extent the rate of germination. Common- 
vetch seed will germinate in a temperature of 50° F. or lower, but at 
such low temperatures the germination is slower than at 60° or 70° F. 
Table 2. — Germination tests of the seeds of common vetch varying in age from 1 to 
20 years 
Age 
Crop 
year 
Date 
tested 
In germi- 
nator 
(days) 
Germination 
test (per cent) 
S. P. I. 
Germi- 
nated 
Hard 
seed 
number 
1920 
1919 
1917 
1916 
1915 
1911 
1907 
1901 
1921 
1921 
1921 
1921 
1921 
1921 
1921 
1921 
10 
10 
10 
10 
10 
7 
7 
6 
100 
99 
100 
100 
99 
96 
10 


1 


1 



2 years .. . 
18141 
18141 
7708 
Table 3. — Germination tests of the seeds of Oregon vetch grown in stated years at 
various periods after harvesting 
Time elapsed after harvesting (results in percentages) 
Crop year 
3 months 
6 months 
9 months 
12 months 
18 months 
Germi- 
nation 
Hard 
seed 
Germi- 
nation 
Hard 
seed 
Germi- 
nation 
Hard 
seed 
Germi- 
nation 
Hard 
seed 
Germi- 
nation 
Hard 
seed 
1914-15 
100 
97 
97 
100 
100 
100 
99 
100 

2 
3 



1 

98 
97 
100 
100 
100 
99 
100 
1 
3 



1 

98 
100 
98 
98 
100 
100 
100 


2 
2 



99 
98 
100 
100 
100 
100 
99 
1 
1 




1 
99 
97 
100 
100 
99 
100 
100 
1915-16-- 
2 
1916-17 

1918-19 

1919-20 
1920-21 


1921-22 

1922-23 
