Page:An introduction to physiological and systematical botany (1st edition).djvu/319

 Rh plants, or excentric, out of the centre, as in Coffee; in Grasses however it is external. Its direction is either straight, curved, or even spiral, in various instances. The Embryo of seeds that have a single cotyledon, or none at all, is peculiarly simple, without any notch or lobe, and is named by Gærtner Embryo monocotyledoneus.

Cotyledones, the Cotyledons or Seed-lobes, are immediately attached to the Embryo, of which they form, properly speaking, a part. They are commonly two in number; but in Pinus, and Dombeya, the Norfolk Island Pine, they are more, as already mentioned, p. 98. When the seed has sufficiently established its root, these generally rise out of the ground, and become a kind of leaves. Such is the true idea of the organs in question, but the same name is commonly given to the body of the seed in the Grass and Corn tribe, the Palms, and several other plants, thence denominated monocotyledones, because the supposed Cotyledon is single. The nature of this part we shall presently explain. It