4. The flower has a distinct odor.
5. Various species of insects visit the flowers for pollen. Many insects secure pollen without effecting pollination.
6. In a rather hasty microscopic examination, no very apparent difference was detected between the pollen from large and small stamens.
7. A very important function of the observed arrangement of stamen and pistil in S. rostratum seems to the writers to be that of support for the visiting insect.
8. It might seem that the pollen from the small stamens is of much more importance in the process of fertilization than Professor Todd suspected, especially since it seems that there is much more certainty of the pollen from the small stamens reaching the pistil than there is of that from the large stamen. The fact that there is some question as to the fertility of the pollen from the large stamen in all cases, and that in the case of another plant stamens of somewhat similar arrangement seem to have lost entirely their direct reproductive function, would indicate the same.
9. In a limited number of cases the pollen from the large stamen of a flower seems to be fertile on its own stigma, as well as upon the stigma of a flower opening simultaneously on the opposite side of raceme.
10. Spontaneous self-pollination seems sometimes to occur.
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.