. The elements of botany for beginners and for schools. Botany. SECTION G.] STEMS. 45. has three forms of branches : 1. Those that bear ordiuary leaves expanded iu the air, to digest M'hat they gather from it and what the roots gather from the soil, and convert it into nourishment. 2. After a while a second set of branches at the summit of the plant bear flowers, which form fruit and seed out of a portion of the nour- ishment which the leaves have pre- pared. 3. But a larger part of this nourishment, while iu a liquid state, is carried down the stem, into a third sort of branches under ground,
. The elements of botany for beginners and for schools. Botany. SECTION G.] STEMS. 45. has three forms of branches : 1. Those that bear ordiuary leaves expanded iu the air, to digest M'hat they gather from it and what the roots gather from the soil, and convert it into nourishment. 2. After a while a second set of branches at the summit of the plant bear flowers, which form fruit and seed out of a portion of the nour- ishment which the leaves have pre- pared. 3. But a larger part of this nourishment, while iu a liquid state, is carried down the stem, into a third sort of branches under ground, and accumulated in the form of starch at their extremities, whicli become tu- bers, or deposito- ries of prepared solid food,—just as in the Tuniip, Carrot, and Dah- lia (Fig. 83-87), it is deposited in the root. The use of the store of food is obvious enough. In the autumn the whole plant dies, except the seeds (if it formed them) and the tubers ; and the latter are left disconnected in the ground. Just as that small portion of nourishing matter which is deposited iu the seed feeds the embryo when it germinates, so the much larger portion deposited in the tuber nourishes its buds, or eyes, when they likewise grow, the next spring, into new plants. And the great supply enables them to shoot with a greater vigor at the beginning, and to produce a greater amount of vegetation tiian the seedling plant could do in the same space of time; which vegetation in turn may prepare and store up, in the course of a few weeks or months, the largest quantity of solid nourishing material, in a form most available for food. Taking advantage of this, man has transported the Potato from the cool Andes of Chili to other cool climates, and makes it yield him a copious supply of food, especially important in countries where the season is too short, or the summer's heat too little, for profitably cultivating the principal grain-plants. 111. The Corm or Solid Bulb, like that of Cyclamen (Fig. )
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Keywords: ., bookpublishernewyorkamericanboo, booksubjectbotany, bookyear1887
