For we must remember that it is the union of the sexual elements of individuals of the same form, for instance, of two long-styled forms, which results in sterility; while it is the union of the sexual elements proper to two distinct forms which is fertile.
Izan ere, gogoratu behar dugu forma bereko banakoen elementu sexualen batzea dela antzu gertatzen dena, adibidez, estilo luzedun forma birena, forma ezberdin bi duten banakoen elementu sexualen batzea ugalkor gertatzen den bitartean.