spirally Twisted Races. 545 



as has been observed elsewhere in intermediate races, 

 and especially in the tricotyls (see page 439). 



Secondly, I call the attention of the reader to the 

 remark which I made hi the previous chapter (j^ 16, p. 

 511) with regard to selection. Even as hi the case of 

 fasciation, a double selection, by the visible characters 

 of the seed-parents and by their hereditary value, cannot 

 here be carried out under the ordinary conditions of the 

 experiments. The most valuable character to select by, 

 the hereditary coefficient, fails, and in consequence of this 

 the improvement of the race, wdiich in the case of the 

 tricotyls so soon resulted in a proportion of from 70- 

 90%, obviously cannot be carried to its full height here. 

 Nothing less than a lucky chance or the conducting of 

 the experiment on a much larger scale can bring this 

 about. In the eighth generation I compared the heredi- 

 tary coefficients of ten parents. They ranged between 

 10 and 55% ; but as only from 100-140 offspring of each 

 parent could be compared, the percentage numbers did not 

 seem to me to be of much importance from the point of 

 view of selection. In the 9th generation I saved the 

 seeds from over 100 very finely twisted individuals, in 

 the hope of still being able to carry out an experiment in 

 selection by hereditary coefficients. 



I shall now give a detailed description of the whole 

 experiment.^ The starting point of my race was formed 

 bv two individuals with a twisted main stem which flow- 

 ered in 1885 in a culture sown in 1884 in mv o-arden. 

 All the remaining plants were destroyed before they 

 flowered. 



In 1886 I obtained a second generation from their 

 seeds. As I have already mentioned, I w^as not at that 



* Annals of Botany, Vol. XIII, No. LI. Sept. 1899. p. 40T. 



