If so, the position of the ovules, even when one is erect and the other suspended within the same ovarium, would follow the selection of any slight deviations in position which favoured their fertilisation, and the production of seed.

Several plants belonging to distinct orders habitually produce flowers of two kinds--the one open, of the ordinary structure, the other closed and imperfect.

These two kinds of flowers sometimes differ wonderfully in structure, yet may be seen to graduate into each other on the same plant.

The ordinary and open flowers can be intercrossed; and the benefits which certainly are derived from this process are thus secured.