455

455

Canna

difference as this as equality; powers of growth; and this I believe to have been the result of long-continued self-fertilisation, together with exposure to similar conditions in each succeeding generation, so that all the individuals had acquired a closely similar constitution.

XXX Graminaceæ.

Zea M mays.

This plant is monoecious, and was selected for trial on this account, as no other such plant of this kind having been experimented on.* It is also anemophilous, that is, or it is fertilised by means of the wind; and of such plants only the common beet had alone been tried. Some plants of maize were grown raised in the greenhouse, and were crossed with pollen taken from a distinct plant; and a single plant, growing quite separately in a different part of the house, was allowed to fertilise itself spontaneously. The seeds thus obtained were placed on damp sand, and as they germinated were planted in pairs of equal age on the opposite sides of four very large pots; nevertheless