chunk: cowslips were fertilised with either pollen from the same kind or from a different kind of flower, and the invariable result was that the crosses between the two different types of flowers produced more good capsules, and more seed in each capsule; and as these crosses would be most frequently effected by insects, it was clear that this curious arrangement directly served to increase the fertility of this common plant. The same thing was found to occur in the primrose, as well as in flax (Linum perenne), lungworts (Pulmonaria), and a host of other plants, including the American partridge-berry (Mitchella repens). These are called dimorphic heterostyled plants.