104 



It is, therefore, justifiable to reqxiire that a certain well defined propor- 

 tion of hard husked seeds be included in the germination total. Revision 

 is required of the principles governing this calculation in regard to each 

 particular variety. The statement can, however, already be considered 

 proved that, according to experiments made to date, the figure of 60 per 

 cent, is approximately correct for hard husk in the case of lucerne, and that 

 of one third in the case of red clover. Experimental proof is still required 

 as to the percentages of hard husk existing in the case of white clover, 

 alsike, kidney vetch, bird's foot trefoil, and marsh bird's foot trefoil. 



Broken Seeds. 



The Union of Agricultural Experimental Stations in Germany lays 

 down, in its technical regulations, that " perceptibly broken and/or 

 entirely spoilt seeds, in so far as they are clearly incapable of germinating, 

 must be excluded when determining purity and germinative power." 



According to the text-book of the Austrian Union of Agricultural 

 Stations, " injured and/or greatly shrivelled seeds of the variety to be 

 tested, in so far as they are clearly incapable of germinating," must bo 

 taken out. 



It frequently happens, especially with regard to red clover and kidney 

 vetch (but less often in lucerne and hop clover), that the seed examined 

 contains a very high percentage of grains showing very slight threshing 

 damage. Tf these — i.e., grains of which, say, part of the husk or the tip 

 of one cotyledon is missing — are taken out and grown on, it will be seen 

 that they give healthy shoots. If the latter are planted out in clay dishes 

 containing earth {according to gardeners' methods), they mostly develop 

 into normal plants. One can even go further, and handle in the same way 

 seeds showing considerably greater threshing damage, i.e., those with the 

 entire upper half of both cotyledons missing. A considerable percentage 

 of these shoots can also be brought to production. 



In addition to broken seed, the existence of which is perceptible before- 

 hand, there exist injuries which can only develop in the germination bed 

 (so-called " internal break,") and by which the germ is affected. In this 

 respect the technical instructions lay down the following standard : — 



" All broken shoots should be held not to have germinated 

 if both cotyledons fall off in germination bed. The loss of one coty- 

 ledon shall not be considered important. Shoots with broken 

 rootlets shall be held to have germinated it one or more adventitious 

 roots develop by the final day." 



These instructions may be considered applicable in regard to seed in 

 which injury through breaking only becomes perceptible in the germination 

 bed. But, in respect of seeds with perceptible outer injiny, it naust be 

 stated that their excliision from sowing would be wrong; for they could 

 also give a germ capable of healthy development, with seedlings of which 

 only a small proportion wovdd have one or both cotyledons missing. 



It is, however, extremely difficult to draw a definite Une between those 

 broken seeds whose injuries do not affect the germ, and those which only 

 give weak plants which develop tardily and finally fail. For this reason, it 

 appears that it should be unequivocally laid down as standard that all clover 

 seed wMch shows any outwardly perceptible injury should be excluded both 

 in the purity and the germination tests, although we hnow that a portion thereof 

 can give a germ, capable of development. 



We may, therefore, accept what is laid down in the text-book, i.e., 

 that " shoots with broken rootlets are held to have germinated, if on& 

 or more adventitious roots develop by the final day." But what is laid 

 down regarding the exclusion of clover seed with an ovxtwardly perceptible 

 injury should be more clearly defined. Instead of the wording which 



