The higher plants, like the higher animals, bequeath to their offspring more or less of nutriment and structure. Superior organisms of either kingdom do not, as do all inferior organisms, cast off their progeny in the shape of minute portions of protoplasm, unorganized and without stocks of material for them to organize; but they either deposit along with the germs they cast off, certain quantities of albuminoid substance to be appropriated by them while they develop themselves, or else they continue to supply such substance while the germs partially develop themselves before their detachment. Among plants this constitutes one distinction between seeds and spores. Every seed contains a store of food to serve the young plant during the first stages of its independent life; and usually, too, before the seed is detached, the young plant is so far advanced in structure, that it bears to the attached stock of nutriment much the same relation that the young fish bears to the appended yelk-bag at the time of leaving the egg. Sometimes, indeed, the development of chlorophyll gives the seed-leaves a bright green, while the seed is still contained in the parent-pod. This early organization of the phænogam must be supposed rudely to indicate the type out of which the phænogamic type arose. On the foregoing hypothesis, the seed-leaves therefore represent the primordial fronds; which, indeed, they simulate in their simple, cellular, unveined structures. And the question here to be asked is--do the different relations of the parts in young monocotyledons and dicotyledons correspond with the different relations of the primordial fronds, implied by the endogenous and the exogenous modes of growth? We shall find that they do. [Illustration: Figs. 111–122.]