Tricotyloiis Half Races. 389 



attained its niaximuni in 15%. The latter occurred 

 amongst the 300 seedlings from the seeds of a daughter 

 plant of one of the two tetracotylous grandparents. 



In the last three generations the maximum ratios 

 were, therefore, 12, 11 and 15%, indicating no advance 

 of any significance. 



Polygonum Convolvulus. A tricotylous plant flow- 

 ered in 1888, in isolation, in my garden. Its seeds gave 

 rise to normal seedlings only (1889). From their seeds, 

 ahout 4000 in all, 1450 seedlings were raised, and 12 of 

 them were tricotylous, i. e., 1% (1890). I harvested the 

 seeds of six tricotylous plants separately, and ohtained 

 ratios from 1 % to 2.4% in sowings of about 1000 seeds 

 each. Of these, 12 seed-parents produced only about 

 1% in the next generation in the spring of 1892; two 

 of them, however, produced 1.5 and 2%. Seventeen 

 plants were planted out. In their crop (April 1893) the 

 proportion of tricot3ds varied from 0.5 to 2% in lots of 

 200 and 400 seedlings, and twelve tricotyls succeeded in 

 flowering. The next generation (April 1894) contained, 

 in the best cases, 2.8% tricotyls ; the next one, to 2% 

 from 8 seed-parents (1895) ; and the last, or ninth, again 

 2% only. 



Silcne conica. In 1892 I had a few tricotyls in 

 flower from seed received by exchange from another 

 botanical e^arden. Their seed ^-ave 3 tricotvls pmonest 

 1000 seedlings. I planted these out, together with some 

 dicotylous seedlings, and in May 1894 I had from 0.2 

 to 1% tricotvls in everv lot of 350 to 800 seedlino^s. 

 Eii^ht tricotyls were planted out and in the spring of 

 1895 their harvest gave a proportion of only 2% and 

 less. From these T obtained in 1895 a fourth generation, 



