Eversporting I 'arietics. 23 
The remarkable fistulous and monophyllous varieties, so 
well known as examples of partial atavism, are further 
instances of eversporting types (Vol. I, Fig. 38, p. 193, 
and Fig. 15 of this volume), together with the viviparous 
grasses (Poa alpina liuipara, Poa bnlbosa livipara, etc.) 
and a number of other viviparous forms such as Agave 
vk'ipara and so forth. 1 If the constant variety corre- 
sponding to a certain intermediate race does not exist, 
this latter is usually classed as a variety in the case of 
middle races, but as a heritable anomaly in the case of 
half races. 
It is, further, very probable that many natural spe- 
cies which attract attention by the high degree of vari- 
ability of some particular character are really in a way 
intermediate races, i. e., that they owe their multiformity 
to the co-existence of two antagonistic characters. In- 
stead of entering further into this very attractive subject 
I shall content myself with citing the case of Acacia 
dk'ersi folia which owes its name and its nature to the 
conflict between the two characters of bipinnate leaves 
and flattened petioles without leaflets (phyllody of the 
stalks). 
The question of the constancy of these intermediate 
races is a very important one. I propose to deal with 
it when referring to individual cases in detail; and the 
only general statement I shall make now is that both con- 
stant and inconstant intermediate races exist. On the 
one hand there are those cases in which an overstepping 
of the limits between these two races is apparently as 
rare as the mutations by which new species arise, and 
1 See GOEBEL, Organografihie, I, pp. 153-159; E. H. HUNGER, 
Ueber einige vivipare Pflamen. Diss. Rostock, 1887. Bot. Jahresber., 
1888, T. XVI, I, p. 421, and also, especially, CLOS, in Actcs du congrcs 
international dc botaniquc, Paris, Sept., 1900, p. 7. 
