The Periodicity of Semi-Latent Characters. 325 
the doubling was seen to increase in intensity in the same 
way. 
BRAUN, in his great work on the rejuvenescence of 
plants, has discussed the part played by periodicity in 
normal development with great thoroughness and clear- 
ness. 1 In the whole plant and also in the separate orders 
of branches the vigor of life goes up and down. The in- 
Fig. 61. Chclidonium inajus plenum. A, a normal flower 
with four petals ; B and C, flowers with five petals ; D, a 
flower with eight well-developed petals and two petaloid 
stamens. 1-5, the transition between stamens and petals. 
dividual strength of the plant is perpetually fluctuating, 
affecting the size of the leaves, the length and thickness 
of the internodes, the number of leaflets in compound 
leaves, the number of rays in the umbels, the ramifica- 
tions in the inflorescences, the number of florets in the 
1 A. BRAUN, Verjungung, pp. 23-55, 75-76, 90 etc. See further: 
HEINRICHER, Biolog. Ccntmlblatt, Vol. XVI, No. i, pp. 13-14. Po- 
KORNY, Sitzber. d. Acad. d. Wiss. } Vienna, 1875, Vol. 72, pp. 527-547. 
