. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. 2o8 Science of Plant Life the plumule. The cotyledons are the first leaflike organs of the plant. The hypocotyl is the first stem, and the plumule is the first bud. No root is foimd in the embryo; but when the seed germinates the h5T)ocotyl elongates, and from its end the primary root de- velops. The cotyledons at first absorb food from the en- dosperm and later expand into photosynthetic organs, which become green when exposed to the light.' The plimiule grows upward to form the st
. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. 2o8 Science of Plant Life the plumule. The cotyledons are the first leaflike organs of the plant. The hypocotyl is the first stem, and the plumule is the first bud. No root is foimd in the embryo; but when the seed germinates the h5T)ocotyl elongates, and from its end the primary root de- velops. The cotyledons at first absorb food from the en- dosperm and later expand into photosynthetic organs, which become green when exposed to the light.' The plimiule grows upward to form the stem. All these early changes are made at the expense of the food in the endosperm. The bean seed consists merely of the embryo with a seed coat about it. The food ^ , ^ J in this seed has already been Fig. 124. Development of mangrove seed- _ â ' lings. This small tree grows on soft mud absorbed into the cmbryo and flats in the tropics and semi-tropics. The gtored in the greatly tHckcned seed {A and C) germinates while still at- . tached to the tree and forms an embryo a COtylcdonS ; that IS, the yOUng foot or more in length. The embryo gmbryo has Continued its finally drops endwise hke an arrow into . , . the mud and starts a seedling (D). grOWth m the SCCd Until it has all the food inside itself. The parts of the embryo are the same as in the castor bean, but the cotyledons are thick and contain a great supply of food for the young plant. The bean is an ex- ample of a large class of plants, including the pea, squash,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Transeau, Edgar Nelson, 1875-1960. Yonkers-on-Hudson, N. Y. , World Book Co.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1921
