The Periodicity of Semi-Latent Characters. 331 
Tagetcs 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. 
Capsella Hecgcri, the new species described by SOLMS/ 
produces reversions to C. Bnrsa pastoris on its weak lat- 
eral branches and, according to the same author, the 
same phenomenon is exhibited by those varieties of Nas- 
turtium pahistre which have been lumped together into 
the genus Tetrapoma. Papavcr somniferuni polyccpha- 
hnn 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 
3 H. GRAF zu SOLMS-LAUBACH, Crucifcrenstudicn, Botan. Zei- 
t n rig, 1900, Pt. X, p. 167. 
