258 



BOTANICAL GAZETTE 



[OCTOBER 



different on different parts of the main spike of a plant and on differ- 

 ent branches; and (2) are they different for annuals and biennials, 

 provided that the individual strength is in both cases as great as 

 possible ? The following experiments will show that the first ques- 

 tion is to be answered in the negative, but the second in the afiirma- 

 tive ; or in other words, the percentage figures depend upon individual 

 vigor of the plants, and this 'between the widest possible Jm ts. 



The second generation of mutant no. 3, cultivated in 19 13, was 

 the most vigorous of all my annual cultures, as already mentioned. 

 I chose for my experiment, therefore, the strongest individual of 

 this group, having the largest supply, of pollen in its anthers, and 

 fertilized its flowers on the main spike and on a lateral branch in 

 small bags, each with its own pollen. At the time of harvest I 

 separated the fruits in groups of 10 each; there were 4 of these 

 groups on the main spike and 2 on the branch. In the spring of the 

 following year (1914) I sowed the seeds of these 6 lots separately. 

 I counted the seedlings in the stage shown in fig. i without trans- 

 planting them. The cana were easily distinguished from the 

 Lamarckiana by their narrower leaves and gray color. There were 

 a mmiber of dwarfs, which combined with this character those of 

 cana and will be called cana-nanella. I have planted them out 

 after finishing the countings and found them true dwarfs of the 

 cana type. About a dozen of them flowered as annuals, and some 

 flowered the following year as biennials. The result of the count- 

 ings is given in table III. 



TABLE III 



Number of 

 seedlings 



Percentage of 



Percentage of 

 cana-nanella 



Percentage 

 together 



A, main spike 



base 



second group 

 third group. . 

 top 



B, lateral branch 



base 



top 



57 

 114 

 121 

 129 



9S 

 94 



40 

 30 

 31 

 35 



39 

 31 



5 

 4 

 4 

 5 



4 

 II 



45 

 34 

 35 

 40 



43 

 42 



The rrieans for the whole plant are 34, 6, and 40 per cent. It is 

 easily seen that the deviations from the means fall within the 



