3i8 PLANT-BREEDING 



hue, and bearing inside the corolla numerous spots in highly 

 variable numbers. Such spots are seen in both the parents, 

 but most beautifully developed in the red species. Many 

 other instances could be given. The hybrid of the common 

 and the small-flowered evening primroses (CEnothera biennis 

 and (En. muricata) has the flovv^ers of one and the spikes of 

 the other parent. In the culitivated violets the size and yel- 

 low tinge are derived from one of the parents, the Viola 

 lutea grandiflora, and so on. 



As a rule some characters of one or the other parent may 

 be more or less easily recognized in the hybrid, but others 

 are so intricately mingled that our knowledge is wholly insuf- 

 ficient to single them out. Each of them may be impeded 

 in its development by the others, and as long as we do not 

 understand the laws by which such mutual hindrances are 

 governed, it is impossible to give more than a superficial 

 analysis. 



Crosses may give us an insight into the nature of unit- 

 characters in still another way. Many so-called characters 

 are in reality composite entities and it is by means of crossing 

 that they can be divided into their constituent units. As 

 an instance I select the color of the flowers and especially 

 that of the cultivated snap-dragon (x^ntirrhinum majus). 

 Its large and bright corollas strike our eyes by their fiery 

 red, and on a closer inspection show a yellow spot on the 

 under lip, and a paler tinge on the tube. These deviations 

 from the general color may be considered as indications of 

 its composite nature. Besides this species a white variety 

 is largely cultivated. It is not absolutely white, but lacks 

 the red dye and the yellow tinge of the main parts. The 

 yellow spot on the under lip, however, has not disappeared, 

 but is still visible, and almost as well developed as in the 

 red species. Here we have the first proof of the build- 

 ing up of the original type out of more simple constit- 



