248 Non-holable Races. 
a pure race with five petals only. For the plants in ques- 
tion were either weaklings, or exhibited pleiopetalous 
flowers on other days. I was often able to observe that 
on many plants six-petalled flowers occur on one day but 
not on another. The 6-7-petalled flowers are found 
from the beginning of the flowering period, but the 
higher figures do not occur till later, as is also known to 
be the case in other instances of double flowers. 
In 1887 I moved some plants in which the abnormal- 
ity was well developed, to my garden, where they flowered 
again in the following summer and set eed. These plants 
constitute the first generation of my experiment. Since 
then I have sown seed every year, but only part of the 
plants, sometimes one-half, sometimes two-thirds, pro- 
duced flowering stems in the first year, and I have always 
confined my attention to these, throwing away those 
which did not bloom during the summer. I have some- 
times kept some of the best examples of the half race 
through the winter for secondary experiments, but I shall 
return to these later on. 
During the period 1889-1892 the second to the fifth 
generation of the half race were grown in this manner, 
the extent of the cultures being gradually increased. 
I always harvested my seed from the most abnormal in- 
dividuals, which I selected by simply cutting off the 
flowers with five petals from all the plants. The numbers 
of these on the individual plants were recorded in some 
years but not in others. Pollination was left to the 
bees, but no definite effects of cross-fertilization have 
been traceable in the results of the experiments. 
The first two years of the experiment (1889 and 
1890) need only a brief reference. Plants without pleio- 
petalous flowers or with only very few, were removed 
