11. The percentage of cases in which seeds develop in those flowers in
which artificial pollination is effected in the same flower or in two
flowers of the same raceme is much smaller than when cross-pollination
is effected by insects, reaching, in the case of the somewhat limited
experiments of the writers, only as high as 28.5 per cent. Whether
this is partially due to the method of applying the pollen or not
has not been determined; whether the seeds produced by these cases
of pollination of the same flower or flowers on the same raceme are
capable of germination or not has not yet been determined. It might
be suggested that the low percentage of cases is due to a lack of
fertility in the pollen of the large stamen.
12. Estimated from the number of seed pods which normally develop, the
number of flowers in which pollination is not effected is very small,
not reaching, in the observations of the writers, much over six per
cent.
Cassia chamæcrista.
1. Right- and left-handed flowers are produced at the same time on
the plant. When several plants are taken, the number of right-and
left-handed flowers produced is practically the same.
2. So far as observed, two flowers were never seen open at the same
time on a cluster, nor was a bud ready to open the following morning
ever found on a cluster with an open flower. Thus, cross-pollination
between flowers on the same cluster would not be possible, as it
frequently is in _S. rostratum_.
3. So far as the writers have been able to ascertain, there is no
law governing the producing of right-and left-handed flowers on the
opposite sides of the main axis.