10
inches, or as 100 to 91. So that the crossed plants now showed a decided
advantage over their self-fertilised opponents.
22. POLEMONIACEAE.--Nemophila insignis.
Twelve flowers were crossed with pollen from a distinct plant, but
produced only six capsules, containing on an average 18.3 seeds.
Eighteen flowers were fertilised with their own pollen and produced ten
capsules, containing on an average 12.7 seeds, so that the seeds per
capsule were as 100 to 69. (5/25. Several species of Polemoniaceae are
known to be proterandrous, but I did not attend to this point in
Nemophila. Verlot says 'Des Vari?t?s' 1865 page 66, that varieties
growing near one another spontaneously intercross.) The crossed seeds
weighed a little less than an equal number of self-fertilised seeds, in
the proportion of 100 to 105; but this was clearly due to some of the
self-fertilised capsules containing very few seeds, and these were much
bulkier than the others, from having been better nourished. A subsequent
comparison of the number of seeds in a few capsules did not show so
great a superiority on the side of the crossed capsules as in the
present case.
The seeds were placed on sand, and after germinating were planted in
pairs on the opposite sides of five pots, which were kept in the
greenhouse. When the seedlings were from 2 to 3 inches in height, most
of the crossed had a slight advantage over the self-fertilised.
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