830 WEED FLORA OF IOWA 



ripened at a higher temperature. The seeds of blue grass when 

 planted soon after maturity did not germinate in darkness but 

 under the influence of light 88 per cent germinated. In spring, 

 however, the germination was equally good in darkness and light. 



Cieslar found that light influenced germination. It would seem 

 from this and other investigations that structure, the oxygen, sub- 

 stratum moisture, temperature, light, in short, the ecology and 

 structure as well as physiology play an important part in germin- 

 ation. 



There are many other contributions, but most of these papers 

 will be found recorded in the literature cited by Vandevelde, Harz 

 and Nobbe. 



American work. — Connecticut. — The pioneer work in this coun- 

 try was done by Profs. E. H. Jenkins and Warneke, of the Con- 

 necticut Agricultural Experiment Station. 



Miss Mary G. Jagger and E. H. Jenkins report the results of 

 analyses for 1908-1909-1910-1911, and note the character of the im- 

 purities of seed found in the Connecticut market. 



North Carolina. — Gerald McCarthy, of the North Carolina Agri- 

 cultural Experiment Station, published an elaborate paper on the 

 subject in which he gave the details of an extensive investigation 

 carried on in North Carolina on germination of seeds. 



Michigan. — Some excellent work was done by Prof. ~W. J. Beal 

 who reported results of germination of clover seeds furnished by 

 seedsmen. From seeds grown on moist paper the results of the 

 germination showed that large red clover had a germination of 

 88 per cent, medium red clover 88 per cent, white clover 84 per 

 cent and alsike clover 64 per cent. Prof. Beal called attention to 

 the difference in germination of seeds when grown in sand and in 

 blotting paper. From seeds grown in sand the following results 

 were obtained: Medium clover had a germination of 76 per cent, 

 white clover 92 per cent, red clover (two separate lots) 70 and 56 

 per cent. 



A later report of Prof. Beal gives two tests of twelve years old 

 clover seeds in both of which the germination was 35.8 per cent. 



Subsequent reports on the vitality of clover and other seeds were 

 also made. 



Prof. Beal also reports tests on seeds sent by farmers. Fifty- 

 eight samples ranged from 25 to 97 per cent, seventeen being above 

 90 per cent. He early called attention to the presence of rib grass 

 in clover seed. Recently he has published an exhaustive bulletin 

 on the seeds of Michigan weeds with excellent figures made by 



