12 MISSOURI AGR. EXP. STA. RESEARCH BULLETIN NO. 17 



extensive previous work of this kind outside of this Agricultural Ex- 

 periment Station of which any record was found, was that of Fawcett 1 

 who collected and planted ninety-two samples of seeds, representing 

 fifty-two species. The collection made at the Missouri Agricultural 

 Experiment Station in 1908 (described in the first part of this bulletin) 

 consisted of ninety-three species of seeds. 



OBJECTS OF THE INVESTIGATION 



The main objects of this investigation were : first, to find if seeds 

 have a rest period; second, what species are subject to the resting 

 phase; and third, whether the rest period can be broken, how and 

 also the effects of various treatments on dry and moist seeds. Inci- 

 dentally, it was hoped that light might be thrown upon various in- 

 teresting questions pertaining to the behavior of seeds in farm and 

 garden practice as well as in nature. For example, the behavior of 

 the common cocklebur (Xanthium canadense, Mill.), indicates that 

 these seeds are able to remain in the soil for two and even three 

 years before germinating. Moreover many wild plants, mostly weeds, 

 spring up from the soil in large numbers at certain times during the 

 season. In the latitude of Missouri some begin to sprout before 

 freezing weather is over in late winter or very early spring; others 

 sprout while the soil is still cold during March and April; and still 

 others do not begin to grow until the arrival of settled weather in 

 June or July. 



It was thought best to disregard the many absorbing questions 

 that might claim attention during an extensive seed study, and con- 

 fine the investigation mainly to the testing of as many species of seeds 

 as possible to find which have a rest period and whether this phe- 

 nomenon appears to be confined to isolated species, or is peculiar to 

 certain genera or orders. 



Previous preliminary tests with seeds at this station having shown 

 that approximately 50 per cent of the species worked with seem to have 

 a rest period, it was designed to make the present investigation com- 

 plete and thoro for all the different kinds of seeds commonly grown 

 in the vicinity of Columbia. 



Experiments in 1911. Collecting began in the spring as the first 

 seeds commenced ripening. The plan of the experiment called for 

 collecting the seeds just at the time when they were considered to be 

 fully matured. In some cases it was difficult to decide just when this 

 stage was reached, but it was assumed that they were mature when 

 they began to fall naturally, or when the pericarp (pod or fruit) was 

 ripe. 



1. Fawcett, H. S., Proc. Iowa Acad. of Science, No. 38, vol. 15. 



