196 Observation of the Origin of Varieties. 



wig's ray-curves^ may also indicate the existence of a 

 latent character, which, if it could be made active, might 

 perhaps give rise to the double variety of the species. 



If we now examine the double varieties of the com- 

 posites, we see that the structure of their inflorescences 

 corresponds in every detail with that of Chrysanthenunn 

 segetuni plenum. The amount of doubling is always 



Fig- 35- Chrysanthemum coronarium. 



highly variable. The best cases reveal no tube florets 

 as in the case of Chrysantheniuni inodoruni in Fig. 34, 

 p. 184. But if one looks between the ligulate florets 

 small yellow tubes will be found in no inconsiderable 

 quantity. This is true of Calendula officinalis and many 

 other species. Such flowerheads are usually sterile, for 



^ May not the secondary maxima on the negative side similarly 

 indicate the variety without ray-florets, the Var. discoidca (See §8, 

 pp. 78-79 and Fig. 9, p. 80). 



