THORNLESS BLACKBERRY 221 



One seedling in particular, grown in 1906, had 

 exceptional qualities, and the subsequent stock 

 was largely grown from the fruit of this single 

 bush. Like its fellows, it bore strains of half a 

 dozen races of high-grade market berries, 

 blended with the thornless strain. 



Of course each successive crossing with a 

 bearer of good fruit meant the introduction of 

 thorns in the seedlings of the next generation. 

 This was inevitable, since of course all the bear- 

 ers of commercial blackberries were bearers also 

 of thorns. The Himalaya in particular is an 

 exceedingly thorny bush, and the otherwise com- 

 mendable Lawton is an almost equal offender. 

 But whereas these thorny shrubs were pre- 

 potent in their influence over their direct 

 offspring as was expected, some of their 

 grandchildren always reverted to the thornless 

 state. 



And so here, as in various other experiments 

 already described, advance was made by indi- 

 rection. We are forced to seesaw back and forth 

 in successive generations between thorny bushes 

 and thornlessness ; yet on the whole there was 

 progress, inasmuch as each successive generation 

 gave better qualities of fruit, and each alter- 

 nate generation the recurrence of the thornless 

 condition. 



