I was then satisfied
as to the purity of the isolated strain. Next year I sowed a new mixture
in [496] order to isolate the reputed pure _grandiflorum_ type. During
the beginning of the flowering period I ruthlessly threw away all plants
displaying less than 21 rays in the first or terminal head. But this
selection was not to be considered as complete, because the 13-rayed
race may eventually transgress its boundary and come over to the 21 and
more. This made a second selection necessary. On the selected plants all
the secondary heads were inspected and their ray-florets counted. Some
individuals showed an average of about 13 and were destroyed. Others
gave doubtful figures and were likewise eliminated, and only 6 out of a
lot of nearly 300 flowering plants reached an average of 21 for all of
the flowers.
Our summer is a short one, compared with the long and beautiful summer
of California, and it was too late to cut off the faded and the open
flowers, and await new ones, which might be purely fertilized after the
destruction of all minor plants. So I had to gather the seed from
flowers, which might have been partially fertilized by the wrong pollen.
This however, is not so great a drawback in selection experiments as
might be supposed at first sight. The selection of the following year is
sure to eliminate the offspring of such impure parentage.
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