Xo. 509] THE CATEGORIES OF VAT! I A 77 OA' 



2^9 



Retrograde varieties, according to De Vries, are 

 sharply distinguished from fluctuations. They are, as a 

 rule, constant from the start, and differ from the type 

 in only one or at most a very few respects. 



parent loss of some quality and rarely in a positive manner by acquir- 

 ing a character seen in allied species." " By far the greatest part 

 of the ordinary garden-varieties differ from their species by a single 

 sharp character only. In derivative cases, three or even more such 

 characters may be combined in one variety, for instance, a dwarfed 

 variety of the larkspur may at the same time bear white flowers or even 

 double white flowers, but the individuality of the single characters is 



These varieties, says De Vries, "do not possess any 

 thing really new." The loss of a character is merely 

 apparent, "On a closer inquiry we are led to the as- 

 sumption of a latent or dormant state. The presumably 

 lost characters have not absolutely, or at least not per- 

 manently disappeared. They show their presence by 

 some slight indication of the quality they represent, or 

 by occasional reversions. They are not wanting, but 

 only latent." In other words, the only difference be- 

 tween retrograde varieties and the types is the latency 

 or patency of certain characters. The same kinds of 

 pangens are present in the germ plasm of both. 



Elementary species, on the other hand, 



number and height of the flower stalks, the breadth and incision of the 

 petals, the forms of the fruits, and so on. Every one of the two 

 •hundred forms included in this collective species has its own type, 



difference. 



The most important distinction which De Vries draws 

 between retrograde varieties and elementary species is 

 a physiological one. They 



