324 Nutrition and Selection. 
visible development of semi-latent characters. Of almost 
equal importance is the individual strength of the young 
plant, which, however, is the result of the operation of 
external factors during preceding periods of time, which 
may be weeks or months or even years. The stronger 
a bud is, the more is it liable to produce anomalies. 
This phenomenon is most clearly seen in the periodic- 
ity of the manifestation of anomalies by the same plant, 
and in the parallel between this manifestation and the 
gradual increase and subsequent decline in strength, either 
of the whole individual or of the succeeding orders of 
its branches. 1 This periodicity has been exhaustively 
studied in the five-leaved clover, and we have become 
familiar with instances of it in several other species. 
It remains now therefore to examine the nature of this 
process from a more general point of view. 
For this let us select a concrete instance. 
In gardens a double form of Chelidonium inajns is 
often found in which, as a rule, the doubling is only slight, 
and seldom consists in the production of more than 
16-20 petals per flower (Fig. 61). On the plants in my 
cultures this doubling regularly increases from the spring 
until the summer, both on the main stems of plants in 
their first year and on the lateral stems of plants that 
have been wintered. For instance in May all the flow- 
ers were single, i. e., with four petals (Fig. 61 A). With 
June the number began to increase, and many flowers with 
6 and 7 and occasional ones with as many as 10 petals 
occurred : whilst in the second half of June the majority 
had 12 to 14 and some 15 and 16 petals. Every year 
1 Over lict pcriodisch optreden dcr anomalien oft monstreuse 
plantcn. Bot. Jaarb., Gent, Vol. XI, 1899, p. 46, and Ueber die Pen'o- 
dicitat dcr particllen Variationen, Ber. d. d. hot. Ges., Vol. XVII, 
1899, p. 45. 
