324 Nutrition and Selection. 



visible development of semi-latent characters. Of almost 

 equal inii)cjrtance 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.-^ 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 Chelidonhini majus 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 



* Over hct pcriodlsch opfredcn dcr anomaJicn of> movsfrcuce 

 planten. Bot. Jaarb., Gent, Vol. XI, 1899, p. 46, and Ucber die Pcrio- 

 dicitdf der partiellen Variationen, Ber. d. d. bot. Ges., Vol. XVII, 

 1899, p. 45. * 



