Half Races and Half Curves. 31 
side of the corolla in a half race of Linaria vulgaris 
which I have studied for a few generations, and for 
which the half curves have recently been plotted and in- 
vestigated by GARJEANNE. 1 
It is w r ell known that every species has a tendency, 
as the expression is, to vary in certain definite directions ; 
in these the deviations occur fairly frequently, in others 
either not at all or very seldom. The number of anom- 
alies is by no means an unlimited one for a given species, 
hut strictly limited. One expression of this phenomenon 
is the fact that one species tends to produce and repeat 
one particular abnormality, and another species, another. 
This general fact, with which we are familiar in vague 
expressions of this kind, can be made the starting point 
of valuable experimental investigations. For what are 
we to understand by "tendency" in these cases? In my 
opinion simply the existence of a half race or sometimes 
even of an eversporting variety. These two types of 
races are, so far as my experience reaches, perfectly dis- 
tinct, and in numerous cases amenable to experimental 
study; they are things with nothing intrinsically vague 
about them although they are sometimes blurred in their 
manifestation, under a superficial examination, on ac- 
count of the high degree of fluctuating variability which 
they exhibit. 
> 
If we take a plant which presents this tendency to a 
particular anomaly and cultivate its progeny, isolating it 
with an eye to this tendency, we shall usually find that we 
are dealing with an intermediate race of the kind of which 
we have spoken. I shall refer to an instance in the fol- 
lowing section ( 5) ; but this will be only one out of 
1 A. J. M. GARJEANNE, Beobachtungen und Culturversuche ilber 
clue Bluthenanomalie von Linaria vulgaris. Flora, 1901, Vol. 88, p. 
78; with Plates IX and X. 
