The Periodicity of Semi-Latent Characters. 327 



Space does not permit the extension of this hst;^ 

 moreover all I am concerned with here is to show that 

 this scheme also holds good for the distribution of anom- 

 alies on the plant. Unfortunately it often can not be 

 exactly applied because it is complicated with the effect 

 of external influences. Every shoot and system of 

 branches has its susceptible period, during which the 

 external factors which happen to prevail favor the pro- 

 duction of the anomaly, or the type of the species, ac- 

 cording to their nature. But apart from these numerous 

 fluctuations the rule holds good wdiere the material is 

 suf^ciently plentiful to justify the neglect of exceptions. 



In a culture of Specularia Speculum which I had in 

 1892 I found the flowers to be partly tetramerous and 

 partly pentamerous. The pentamerous ones occurred 

 at the top of the stem and of the strongest branches of 

 the second order, whilst all the remaining flowers were 

 tetramerous. A similar difference between apical and 

 lateral flowers is exhibited as a normal character by 

 Adoxa Moschatellina and by many other plants. The 

 Pimis sylvestris of this neighborhood often has its needles 

 combined into groups of three instead of groups of two. 

 Each such group of needles, as is well known, belongs 

 to a single dwarf shoot or spur. I found that the tri- 

 foliate spurs occurred almost exclusively on the stronger 

 branches, and chiefly at their upper Q\\i\ ; but where they 

 did occur they were numerous and closely, packed. As 

 a rule it is the main stem itself which bears them, but 

 sometimes the strongest branches do so as well. 11iere 

 occurred up to 15 trifoliate spurs on the same one year's 

 growth of the stem, all close to the a])cx. mixed with 



^ On tlie question of periodicity in the branching of cereals see 

 ScHRiBAi'x in Journal d' Agriculture pratique, 1800. and Rimpau in 

 Laiidzi'irthsch. Jahrbiichcr, Vol. XXIX. p. 589. 



