Plan fa go Lanceolata Ramosa. 149 



be only partial. In spite of the most careful selection 

 and isolation during the time of llowering this race every 

 year produces plants not one of whose spikes, even when 

 there are a hundred to the plant, exhibits the smallest 

 trace of branching. They are obviously to be regarded 

 as atavists. 



The proportion in which these atavists occur seems 

 to be fairly constant, fluctuating however from year to 

 year. It can be slightly increased or diminished by the 

 choice of favorable or unfavorable seed-parents; but it 

 does not seem possible to effect an essential and per- 

 manent improvement by continued selection, at least not 

 to a degree that would open a chance of altogether elim- 

 inating the atavism. 



In the first years of my cultures I did not pay partic- 

 ular attention to this phenomenon ; moreover my experi- 

 ments were on too small a scale to afford numerical data 

 of any value. But I found atavists as w^ell as raiiiosa- 

 plants every year, although I always collected my seeds 

 from the former. I did not determine the proportion 

 until the fifth generation (1892) was reached. I should 

 state tliat I have isolated my seed-parents every year, 

 cutting off as many as possible of their unbranched ears 

 before they flowered. Pollination which had to be left 

 to the wind w^as therefore confined to the group of se- 

 lected seed-parents, wdiose number scarcely ever ex- 

 ceeded 10. It was as pure as it was possible to have it. 



I obtained the following figures : 



GENERATION PERCENTAGE OF ATAVISTS 



5.— 1892 ^6% 



6.— 1894 50%, 58%, 59% 



7.— 1897 47% 



8.— 1898 45%, 56%, 59% 



8.— 1900 52% 



