The Periodicity of Semi-Latent Characters. iM 



Tagetes africana and T. signata often first exhibit 

 single flowerheads only, but subsequently double ones in 

 increasing numbers on the same plants. The same thing 

 can be seen in Zinnia elegans, and in Althaea rosea the 

 flowers are sometimes seen to become more double as 

 we proceed up the stem. 



Weak lateral buds in variable races often exhibit a 

 special tendency to atavistic variations. This is true of 

 the branches of the highest orders, of the accessory 

 shoots, which are formed in addition to the normal axil- 

 lary bud, of resting buds, etc. But it should be remem- 

 bered that it is just these buds which often develop into 

 very strong branches and become the succulent shoots 

 which tend to reproduce the anomaly rather than the 

 specific type. I have already referred to this exception 

 above. 



CapscllaHeegeri, the new species described by Solms/ 

 produces reversions to C. Bursa pastoris on its weak lat- 

 eral branches and, according to the same author, the 

 same phenomenon is exhibited by those varieties of Nas- 

 turtium palustre which have been lumped together into 

 the genus Tetrapoma. Papaver somnifernm polycepha- 

 him produces flowers without any accessory carpel almost 

 exclusively on the very weak branches which arise from 

 the main stem towards the end of the year when the 

 lateral branches have been cut away. The peloric flowers 

 of Digitalis purpurea are monstrously developed at the 

 apex of the stem and on the strongest lateral branches ; 

 but on the weaker ones they are simple and very regular 

 (Fig. 42, p. 223). 



Such buds can often be induced to develop by cutting 



^ H. Graf zu Solms-Laubach, Crucifcrcnstudicn. Botan. Zci- 

 tnns:, 1900, Pt. X, p. 167. 



