Half Races zvitli Heritable l-asciation. 503 



cties distinguished in the first part of this \-uhinie ( p. 18). 

 In the former case the anomahes are rare and their fre- 

 quency can not be increased by selection to any consider- 

 able extent. In the second case the fasciations occur even 

 in the held in obviously larger numbers ; and it is only 

 necessary to isolate the examples in question in order to 

 be in immediate possession of a race producing fasciations 

 abundantly. These experiments are perfectly analogous 

 to those which we have described in the case of other 

 anomalies and especially to those relating to tricotylous 

 and syncotylous cultures (see page 343). Nevertheless, 

 in the case of fasciations, we have by no means so strin- 

 gent a character to select by, as is presented by the per- 

 centage hereditary values, calculated from the seedlings 

 of tricotylous races, and therefore the subsequent devel- 

 opment of the race after the initial isolation is a matter 

 of much greater difficulty. 



Postponing the consideration of the eversporting vari- 

 eties or intermediate races to the next section, let us here 

 attempt to obtain some insight into the races in which the 

 anomaly occurs more rarely. Unfortunately, in many 

 instances the available data are not yet sufficient to enable 

 us to decide with perfect certainty to which of the two 

 t\ pes a given case belongs. 



Fasciations occur in so many commercial varieties that 

 they are accessible to everybody ; sometimes even the 

 variety owes its name to the frequency of this character, 

 as, for instance, the Sword-elder (Sanibiiciis nigra fas- 

 cia fa) ; or it may be an almost constant attri])ute of the 

 cultivated sorts, as in the Japanese spindle-tree {Ez'0}i\- 

 imis japojiica. Fig. 112). When the varieties are either 

 largely or exclusively multiplied in the vegetative way, 

 it is possible that the anomaly, although only heritable 



