THE VIABILITY OP WEED SEEDS UNDER DIFFERENT CONDITIONS OF 
TREATMENT, AND A STUDY OP THEIR DORMANT PERIODS. 
BY H, S. FAWCETT. 
The viability of a seed is its capacity to live after maturity, and its dormant 
period is the time required for the seed to germinate after being planted. 
A great deal of investigation has been carried on for many years past to 
determine the viability of seeds; more especially of cultivated seeds of the 
farm and garden, but not so much attention has been given to weed seeds. In 
1897 Mr. C. R. Ball of this college published an article on “Seed Testing; Its. 
Importance, History and Some Results, With a Partial Bibliography.” This 
article contains a long and valuable bibliography referring to all the rnost im- 
portant literature before 1897. 
Some of the recent articles on the subject are: Bull. 38 of the Nevada 
Station, on “Nevada and Other Weed Seeds,” with figures of weed seeds by F. 
H. Hillman; “The Germination of Weed Seeds,” by L. H. Pammel and G. M. 
Lummis, 1902; Bull. 58 of the Bureau of Plant Industry, on “The Vitality and 
Germination of Seeds,” by J. W. T. Duvel, and “Rules and Apparatus for Seed 
Testing,” in Circular 34 of the Office of Experiment Stations, 1904. 
The object of the present investigation was to make a comparative study 
of the viability of different species of weed seeds, especially those found in 
cultivated fields and pastures, and to study their dormant periods in order to 
determine if possible any means of destroying these seeds. A test was also 
made of the effect of freezing and thawing on the vitality and the length of 
the dormant period for each species. 
Ninety-two samples of weed seeds, representing fifty-two different species, 
were used. These samples were collected in September, October and November 
of 1904. Care was taken to collect, whenever possible, thoroughly mature seeds. 
The seeds were nearly all collected before they dropped to the ground and when 
.dry they were threshed out and placed in paper envelopes. 
For the germination tests fifty seeds of each sample were placed in sand, in 
boxes, under benches in the greenhouse, and kept as near as possible under uni- 
form conditions. These tests were repeated each month from November until 
May, all the boxes of all previous months being left. All the boxes were kept 
moist and a daily record was kept of the number of seeds germinating. In 
addition to these tests seeds from a large number of these samples were placed 
out of doors in order to expose them to the effects of freezing and thawing. 
The seeds were placed in sacks inside a thin wooden box and a thin layer of 
sand placed around them. The box was then sunk into the ground so that 
the top part was just exposed. These seeds were taken out in April and 
planted side by side with seeds from the same sample that had been in doors 
all winter. ' 
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