External Conditions and Hereditary I 'alues. 487 



the main stem, and tliey prodnee a eorrespondingly smaller 

 number of synowtyls, l)nt only in the proportion of 87 to 

 80%, on an average for 12 plants. If the seeds of single 

 infloreseences are harvested in three lots in such a way 

 that the outer, inner and middle areas are separated, the 

 former generally contain slight- 

 ly more syncotyls, for the fruits 

 in the middle of the head tend 

 to be somewhat weaker. From 

 each of these tlu'ee groups I 

 have allowed the best seedlings 

 to flower and bear fruit, but 

 I found no essential difference 

 in their hereditary values. It 

 appears that improved condi- 

 tions during the early stages of 

 the plant, have some small in- 

 fluence in a positive direction, 

 but crowding in later life and 

 partial removal of the leaves 

 during the flowering period had 

 little noticeable effect (1891). 

 Furthermore a culture on eood 



Fig. 103. HcJianthus annutis 

 syncotyleus. A and B, seed- 

 lings whose plumule has 

 not developed during the 

 course of several weeks ; the 

 syncotyl is abnormally en- 

 larged. C, Amphi-syncotyl- 

 ous plant, also with inhib- 

 ited development of the 

 stem. 



sandy soil, instead of garden 



soil, made no difference in the values (1892). 



Striking exceptions, however, sometimes occurred, for 

 instance in the year 1891, when three plants in my main 

 culture became affected with Pc^iza a short time after 

 flowering, and died, not however without ripening some 

 of their seed. These three produced the smallest values 

 of the whole group. (76, 84 and ^"^^ as against 86 to 

 999f V P>ut perhaps they were the weakest individuals 

 and contracted the disease for this reason. 



