SERICEA AND OTHER PERENNIAL LESPEDEZAS 9 



Germination was high in 1930, very low in 1931, fairly high in 

 1932, and low in 1933. A study was made of the effect of th< 

 time of harvesting on the hardness of the seed. Branches were 

 cut from five individual plants commencing in mid-October when 

 the seed was well formed but still green and continuing at weekly 

 intervals until mid-November. Germination tests showed no con- 

 sistent relation between time of cutting and the percentage of 

 hard seed. 



Table 1. — Percentage of germination and of hard seed in unhidled 

 seed from 5 individual plants, Arlington Experiment Farm, Va., 

 1930-33 





1930 



1931 



1932 



1933 



Item 





















Germina- 



Hard 



Germina- 



Hard 



Germina- 



Hard 



Germina- 



Hard 





tion 



seed 



tion 



seed 



tion 



seed 



tion 



seed 





Percent 



Percent 



Percent 



Percent 



Percent 



Percent 



Percent 



Percent 



Plant No. 1___ 



76.0 



11.0 



3.5 



95.5 



75.5 



18.0 



3.0 



93.0 



Plant No. 2___ 



42.5 



50.0 



.5 



98.5 



8.0 



90.0 



10.5 



88.0 



Plant No. 3___ 



63.5 



17.0 



1.5 



97.5 



20.0 



79.5 



8.0 



90.0 



Plant No. 4___ 



56.5 



14.0 



1.0 



97.0 



64.5 



30.0 



8.5 



88.0 



Plant No. 5___ 



43.0 



18.5 



2.5 



96.0 



46.0 



53.0 



7.0 



89.5 



Treatment of Hard Seed 



Hard seed may be treated by various methods, all designed to 

 break or soften the impermeable outer coat so that water may 

 enter. Such methods include treatment with sulfuric acid, hot 

 water, dry heat, and mechanical abrasion or scarifying. 



All these are effective and their usefulness in practice depends 

 on the economy and convenience of application. The action of 

 winter cold should also be effective, but no data have been 

 secured on this point. In fact, there are some indications that 

 such action is not very effective. Repeated sowing of unhulled 

 seed at Arlington Experiment Farm during winter has never 

 resulted in more than a scattered stand. 



Hot water has been shown to be effective. In one series of 

 experiments by the Bureau of Plant Industry boiling unhulled 

 seed for 15 seconds improved the germination from 6.5 percent to 

 94 percent. In another series of tests it was shown that best 

 results were secured by keeping hulled but unscarified seed for 

 30 to 45 minutes in water at 70° C. (158° F.) or for 1 minute 

 at 90° C. (194° F.). At higher temperatures for 3 minutes the 

 seed was killed. Dry heat was also effective. Seed kept in an 

 oven at 90° C. for one-half hour germinated 94 percent with 

 4 percent remaining hard. In a trial with sulfuric acid it was 

 found that immersion of hand-hulled seed in the acid for 30 to 

 60 minutes resulted in the germination of 98 to 100 percent of 

 the seed. Immersion for 10 minutes was not so effective, 60 per- 

 cent of the seed germinating and 35 percent remaining hard. 



