GRASSES OF IOWA. 

 TA.BLE No. X. 



109 



Blue grass. Poa pratensis. — For convenience of comparison 

 some facts concerning the vitality of four of our common pas- 

 ture and forage grasses have been set forth separately. The 

 seeds of this very valuable lawn and forage grass possesses 

 the lowest vitality of any of our commonly cultivated grasses. 

 Just why this should be is not so evident. Some facts 

 obtained by G. E. Morrow and T. F. Hunt* are of value in 

 solving this problem. They made vitality tests of eighteen 

 samples of blue grass seed from seventeen different prominent 

 seedsmen and also of one sample of seed gathered on the sta- 

 tion grounds. The seed were fi st tested in the Geneva appa- 

 ratus for thirty- eight days, and later the tests were repeated 

 in soil in the open air and in the green house, where they con- 

 tinued from March 14th to July 27th. 



There is such a striking difference in the results obtained 

 from the tests made in the Geneva apparatus and those made 

 in soil that I have tabulated the figures to show this difference, 

 and have added to the column headed "In Geneva apparatus" 

 the results obtained by McCarthy as a standard, those gotten 

 by Parsons, and also those given by fifteen other tests from 

 different sources. The first and fifth columns give the number 

 of samples on which the results are based. 



*I11. Agri. Exp. station BuU. 15: pp. 478-483. 1891. 



