THE PRIMORDIA 59 



observed, the colour being affected, the length hardly or not at 

 all. See this paragraph, first example, p. 55.) 



FOURTH EXAMPLE : A rose-purpHsh subspecies of 

 Centaurea cyanus (one specimen in a rye field, June, 1911) ; 

 marginal florets. — The property length behaves exactly as in 

 the above-mentioned blue subspecies ; it is original, arrested 

 and persistent. The development of the colour follows the 

 same line as in the blue subspecies during the two first periods, 

 the succession being white and rose-purplish. But when the 

 latter colour has reached the value pale (which coincides with 

 the end of the second period in the blue subspecies) the trans- 

 formation into blue does not take place and a third period is not 

 initiated. The second period is protracted, the intensity of the 

 rose-purplish colour increasing gradually till the value intense 

 rose-purplish is reached. This happens when the flower-head 

 is expanded. The primordium rose-purplish is here meta- 

 morphic and arrest ed.^ 



REMARK I. : The above example is interesting with regard 

 to the significance of the term infantile [juvenile, pcedogenetic). 

 We might be tempted to say that the rose-purplish subspecies 

 is infantile in comparison with the blue. Used in that way, the 

 term infantile does not express an exact notion. The rose- 

 purplish subspecies is deprived of the blue colour and therefore 

 infantile with regard to the property blue. But in the blue sub- 

 species the property rose-purplish is arrested in its development 

 when it has reached the value pale ; therefore the blue sub- 

 species is infantile with regard to the colour rose-purplish. 



In other words, each subspecies being considered as a whole, 

 neither of them is infantile. In both the development of the 

 colour follows the same line till the value pale rose-purplish is 

 reached. After that the development continues along two 

 diverging lines. We see, from this very simple example, that 

 the term infantile [juvenile, pcedogenetic) ought to be used with 

 regard to each property separately, but is not strictly applic- 

 able to a species, a subspecies (or even an individual) considered 

 as a whole. 



REMARK II. : In a similar way the terms progressive and 

 retrogressive are ambiguous when applied to the phylogenic 

 relations of specific forms. It might be said, for instance, that 

 the rose-purplish subspecies has been produced by a progres- 

 sive mutation of the blue subspecies with regard to the property 

 rose-purplish; but one might say also that the rose-purplish 

 subspecies is the result of a retrogression with regard to the 

 property blue. The above remarks are not merely linguistic 

 subtleties. In complicated cases, when a number of properties 



^ I don't remember whether it is persistent or deciduous. See about 

 gradation in Centaurea, § 133. 



