Outlines of Lessons in Botany, Part I; from Seed to Leaf by Jane H. Newell
page 23 of 105 (21%)
page 23 of 105 (21%)
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[Footnote 1: The so-called seed of Sunflower is really a fruit. The outer covering is the wall of the ovary, the inner the seed-coat. Such closed, one-seeded fruits are called akenes.] [Footnote 2: The plumule is sometimes visible in the embryo of the Sunflower.] _Bean_. A seed covering. Two cotyledons. A caulicle. A plumule. _Pea_. The same as the Bean. They have also learned how the first leaves in the last three differ from those of the Morning-Glory, being considerably thicker in the Sunflower, and very much thicker in the Bean and Pea. Why should the Morning-Glory have this jelly that the others have not? Why do the first leaves of the Sunflower change so much as the seedling grows? What becomes of their substance? Why do those of the Bean shrivel and finally drop off? By this time some bright pupil will have discovered that the baby-plant needs food and that this is stored around it in the Morning-Glory, and in the leaves themselves in the others. It is nourished upon this prepared food, until it has roots and leaves and can make its own living. The food of the Morning-Glory is called _albumen_; it does not differ from the others in kind, but only in its manner of storage.[1] [Footnote 1: Reader in Botany. III. Seed-Food.] 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 |
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