Partial Variability of Tricotyly. 445 



self has two or three or merely cleft seed-leaves is a 

 question of minor importance, and does no more than 

 furnish a suggestion in starting the experiment. On 

 the average, atavists and hemi-tricotyls are, without 

 doubt, of less value in this respect than tricotyls and. 

 tetracotyls ; but the differences are too small to warrant 

 a choice of seed-parents on this ground. 



The determination of the hereditary value depends, 

 therefore, largely on the extent of the crops. The larger 

 this is for any one individual, the more closely will the 

 value found correspond to that which would be derived 

 from an imaginary harvest, consisting of an infinite num- 

 ber of seeds. Therefore, the best plan would be to make 

 the plants grow as vigorously as possible, and to save 

 the seeds of all fruits from as many branches and sprigs 

 as possible. In practice, however, this cannot be done, 

 since it is far more important to grow as many indi- 

 viduals as possible in a given space. The more numerous 

 the individuals are, the more stringent the selection be- 

 comes ; and, wdiat is far more interesting, at least in 

 working with mixtures, the greater is the prospect of 

 finding any desired particular sort. Unbranched, or al- 

 most unbranched, plants wnth terminal inflorescences only, 

 obviously need much less room than much branched in- 

 dividuals; and larger harvests require relatively too much 

 time to gather. The best plan, therefore, would be to 

 collect only just so much seed from each individual as is 

 necessary for sowing in the following year. 



These considerations suggest the question whether 

 different groups of fruits are alike in regard to hereditary 

 capacity or whether they exhibit, perhaps, considerable 

 differences. Shall we find this capacity to be different on 

 the branches from what it is on the main stem? Will 



