452 Ever-sporting Varieties 



ing circumstances, and if growing near the 

 limits of such regions it will overlap and get 

 into the new area. All other species, which did 

 not acquire the double habit, are of course ex- 

 cluded, with such curious exceptions as those 

 of Kaits. The typical vegetation under such 

 extreme conditions, however, finds explanation 

 quite as well by the one as by the other view. 



Leaving these obvious cases of double adap- 

 tation, there still remains one point to be con- 

 sidered. It is the dwarf stature of so many 

 desert and alpine plants. Are these dwarfs 

 only the extremes of the normal fluctuating va- 

 riability, or is their stature to be regarded as 

 the expression of some peculiar adaptive but 

 latent quality! It is as yet difficult to decide 

 this question, because statistical studies of this 

 form of variability are still wanting. The ca- 

 pacity of ripening the seed on individuals of 

 dwarf stature, however, is not at all a uni- 

 versal accompaniment of a variable height. 

 Hence it cannot be considered as a necessary 

 consequence of it. On the other hand the dwarf 

 varieties of numerous garden-plants, as for in- 

 stance: of larkspurs, snapdragon, opium-pop- 

 pies and others are quite stable and thence are 

 obviously due to peculiar characteristics. Such 

 characteristics, if combined with tall stature 

 into a pair of antagonists, would yield a double 



