T. GooDBY -29 



Widely separated from this group we have another one (2) much less 

 susceptible, comprising 



Cow -grass (English) ... 38-2", | 



AJsike clover (Canadian)... I!7 - f (roup 2. 



Alsike flovfi- (Englisli) ... iS-.", ) 



The great disparity between the figures for the Swedish and the 

 English cow-grass is remarkable and somewhat surprising, and suggests 

 tjie need for much further investigation along these lines. 



A further group (3) comprises varieties which are but very sliglitly 

 susceptible to attack, viz. : 



Sainfoin ... ... ... 7 ) 



White clnvfM- (Wild Cot.swold) ry'y | ^, „„ , 



(English) ... 4-7.-. '"^""P-'- 



(Wild Kontish) 2 ) 



Lastly we have a group (4) made up of 



White rluver (Sutton's .Mammoth)) 



Lucerne [ I iroup 4. 



Trefoil ) 



which appear to be iusu.sceptible to attack. 



A comparison of the indices of susceptibility with the percentages 

 of deformed seedlings shown in Table I reveals the fact that all the 

 members of Group I have a high percentage of deformed seedhugs. 

 Canadian red clover, having the highest index of susceptibihty, has also 

 the highest percentage of deformed seedlings. The parallel does not hold 

 throughout the group, however, for Wild EngHsh red clover, which has 

 the second highest percentage of deformed seedlings, has the lowest 

 index of susceptibihty in CTroup 1 . 



The low index of susceptibility shown by English cow-grass, compared 

 with its high percentage of deformed seedlings, is an otitstanding excep- 

 tion to the parallelism of high inde.x of susceptibility with high per- 

 centage of deformed seedlings. 



In the case of Groups 2 and ?> it is not possible to establish a 

 parallel when we have cases like English alsike clover with a lower 

 perci'ntage of deformed seedlings I ban either English white clover or 

 sainfoin, and a much higher index of susceptibihty than either of these. 



These results are in general agreement with those of Amos (1919, 

 pp. 8 and 9), except as to one or two details. He never found sainfoin 

 attacked, whilst I find that the seedlings are very slightly susceptible 

 to attack. 



Tlie results have a practical bearing of considerable importance to 

 the farmer whose land is infested with Tylenchun dipsaci, and whose 

 red clover is therefore hable to attack from this parasite. 



