250 
H. B. SIFTON 
Alsike and Red Clover 
Twelve samples of each of these from the 1902 crop and twelve raised 
in 1903 were used, and the tests were carried on at 18° to 20° C. The curves 
Fig. 3. Longevity curve for timothy. FiG. 4. Longevity curve for alsike. 
are shown in figures 4 and 5. The interesting thing about them is their 
regular decline from the first, making each curve, as far as it has yet gone, 
approach a straight line much more closely than in the case of any other 
crop studied. Both clovers have a larger proportion of long-lived seeds 
(over 15 years) than wheat, but from the standpoint of a practical seedsman 
their longevity is not nearly so great. After eleven years, wheat on the 
average still germinates to the extent of more than 85 percent, but eleven- 
year-old alsike or red clover seed germinates less than 40 percent. (This 
result is calculated from the curve. The actual germination obtained in 
the laboratory on eleven- and twelve-year-old samples was much less, but 
the results of later and earlier tests make it evident that the percentages 
obtained in these two years were not correct.) 
The natural expectation would be that the curves for the clovers would 
be almost horizontal at the first owing to the gradual softening of "hard 
seeds" with age. This, in the course of an experiment not yet ready for 
