STUDIES ON ONONIS IN BRITAIN 



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if uneven, transition from O. repens to O. spinosa. There is an obvious mode coinciding 

 with that shown in the pure O. repens colonies, and in both these localities this species 

 abounds, a fact which is clearly shown in Table 1. At the other end of the histograms 

 there is no mode coinciding exactly with that to be expected from normal O. spinosa, 

 through the histogram for the Blackball Rocks colony (Fig. 4F) has a secondary mode 

 in approximately this position. This again is in general agreement with the visual assess- 

 ment of these colonies as shown in Table 1 . 



