Also the questions have brought out the fact that the Bean and Pea have the plumule ready formed in the seed, while the Morning-Glory and Sunflower have not. Why should this be? It is because there is so much food stored in the first two that the plumule can develop before a root is formed, while in the others there is only nourishment sufficient to enable the plantlet to form its roots. These must make the second leaves by their own labor. 3. _Comparison with other Dicotyledons_.--The pupils should now have other seeds to compare with these four. Let them arrange Flax, Four o-clock, Horsechestnut, Almond, Nasturtium, Maple-seeds, etc., under two heads. _Seeds with the Food stored _Seeds with the Food stored outside the plantlet in the embryo itself (Albuminous)_. (Exalbuminous)_. Flax. Four-o'clock. Acorn. Horsechestnut. Almond. Morning-Glory. Maple. Sunflower. Squash. Bean. Pea. Nasturtium. They may also be divided into those with and without the plumule. _Without Plumule_. _With Plumule_. Flax. Maple. Sunflower. Acorn. Horsechestnut. Four-o'clock. Almond. Bean. Pea. Morning-Glory. Squash. Nasturtium. Those with plumules will be seen to have the most abundant nourishment. In many cases this is made use of by man. These last can be again divided into those in which the cotyledons come up into the air and those where they remain in the ground. _In the Air_. _In the Ground_. Bean. Almond. Squash. Acorn. Horsechestnut. Pea. Nasturtium. In the latter the cotyledons are so heavily gorged with nourishment that they never become of any use as leaves. As Darwin points out, they have a better chance of escaping destruction by animals by remaining in the ground. The cotyledons are very good illustrations of the different uses to which a single organ may be put, and the thorough understanding of it will prepare the pupils' minds for other metamorphoses, and for the theory that all the various parts of a plant are modified forms of a very few members.