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Updated: May 29, 2025
If we examine the seed-leaves after the seed has sprouted we shall find them less hard and firm; they have given part of their substance to the embryo. They have also turned greenish in color, while, as we know, the leaves of the embryo, which at first were so white and tiny, have also turned green and grown larger. Between the two embryo-leaves there is a little growing tip.
So even where they are ripe and fall from their pods, he had better keep them until toward Spring before planting, even in the house. If he takes pleasure in examining his seeds, he will find in each one the tiny embryo tucked in between the seed-leaves; in the apple seed the young apple-tree, in the pumpkin seed the young pumpkin vine.
The young plant now no longer depends upon the seed-leaves for its food. Down in the earth the roots are taking in nourishment, and up in the air the little green leaves are also busy supplying food to the growing plant. The little growing tip lengthens into a stem from which a leaf is seen unfolding. This new leaf is not shaped like the embryo-leaves nor like the seed-leaves.
There must be food somewhere, and it is found packed away in the thick seed-leaves, which contain a great deal of starch and a little of some other things. The young plant, under the influence of warmth and moisture, is able to draw out the nourishment from the seed-leaves.
"Let us first direct our attention to the plant at the moment when it develops out of the seed-kernel. The first organs of its upward growth are known by the name of cotyledons; they have also been called seed-leaves. "They often appear shapeless, filled with new matter, and are just as thick as they are broad.
The primary leaves, following the seed-leaves, are different in many species, from the later ones, and the difference is extremely pronounced in some cases of reduction.
There seems however to be a reservoir of nutriment prepared for some seeds besides their cotyledons or seed-leaves, which may be supposed in some measure analogous to the yolk of the egg. Such are the saccharine juices of apples, grapes and other fruits, which supply nutrition to the seeds after they fall on the ground.
Hence the best way is to choose such attributes, as may already be seen in the young seedlings, in the very first few weeks of their lives. Fortunately the seed-leaves themselves afford such distinctive marks, and by this means the plants may be counted in the pans, requiring no culture at all in the garden.
The sap constantly stores up in them plenty of good food. Thus the parent plant provides for the seed, so that when it goes out into the world alone it may not perish until it has learned to care for itself. The food in the seed-leaves is the bank account which starts the young plant in life. When the seed is fully formed, its seed-leaves full of food, its embryo perfect, then we say it is ripe.
For brevity's sake all these cleft and ternate, double cleft and quaternate cotyledons and even the higher grades are combined under one common name and indicated as tricotyls. A second aberration of young seed-plants is exactly opposite to this. It consists of the union of the two seed-leaves into a single organ. This ordinarily betrays its origin by having two separate apices, but not always.
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