Half Races and Half Curve. 35 
by making r. special curve from plants which exhibit the 
largest number of abnormalities, or by making a curve 
from a race bred from such plants. But an improved 
race of this kind remains dependent on selection and high 
nutrition, and is soon lost if these are withheld. 1 One 
instance will suffice. Achillea Millcfoliinn has white 
flowers, but occasional specimens have red ones. From 
this I have bred a race with red flowers, which some- 
times even attain the deep red of dark wine. After four 
years of stringent selection, all the plants in successful 
cultures were more or less red. But if the plants were 
grown too close or were on poor land, more than half 
were white, and when I made further sowings without 
selection the proportion of reds rapidly reverted to its 
original small amount. On the other hand there is on 
the market the well-known Begonia semperfiorens atro- 
pnrpurea Vcrnon as a constant dark brownish red vari- 
ety. 
Eversporting varieties revert rapidly under minus- 
selection, but it is seldom possible to eradicate their char- 
acter altogether as I experienced when working with the 
adnation of the lateral branches to their main stems in 
Aster Tripolium and Bidcns grandiflora, and as I shall 
describe later in greater detail in the case of Celosia cris- 
tata. (See Part II of this volume.) 
In conclusion, we see that in nature as well as in 
cultivation (especially in the case of horticultural vari- 
eties and other anomalies) intermediate forms between 
the original species and its constant variety are often 
met with. The two commonest are the half race and the 
middle race or eversporting variety. The former has 
a half curve, the latter a bilateral one. Both occur in 
1 Vol. I, Part I, 14, p. 122. 
