Evcrs porting Varieties. 21 



call a half race, and No. Ill a middle race. The word 

 race is obviously not used here in the sense of an im- 

 proved rare (Vol. I, p. 80) but simply means a heritable 

 form. Instead of middle race I shall usually employ 

 the more convenient term of eversporting variety.^ 



Two examples to which reference has already been 

 made will serve to illuminate the foregoing discussion. 



EXAMPLES. 



VARIEGATED LEAVES. DOUBLE FLOWERS. 



I. Original species. Green. Simple. 



II. Half-race. Rarely variegated. Occasional petaloid 



stamens. 



III. Eversporting variety. Var. variegata. Var. plena. 



V. Constant variety. Var. aurea. Var. petalomana. 



The parallelism of these two groups rests on the 

 assumption that the same character appearing in a state 

 of full development would give rise to the constant golden 

 and to the fully double varieties;- and that it is by their 

 mixture with the antagonistic character that variegated 

 and half-double varieties arise. The object of this as- 

 sumption is solely to present the matter more clearly ; 

 for in cases of segregation the characters behave slightly 

 differently (see p. 124). 



There are many examples of half races and ever- 

 sporting varieties ; the former constitute a very con- 

 siderable part of the material of teratology and afford 

 suitable material for the experimental study of monstros- 

 ities. The same holds good for many eversporting vari- 

 eties, and I shall have to recur to this point in the second 

 part of this volume with especial reference to twisted 

 stems and fasciations. Half races as a rule exhibit their 



^ See Species and Varieties, Their Origin by Mutation, Chapters 

 XI-XV, pp. 309-459- 



^ See § ig and especially § 24 (on variegation). 



