. A text-book of botany for secondary schools. Botany. ANGIOSPEBMS 237. Fig. 228.—Seed of violet, one figure ahow- ing the hard testa, the other the em- bryo (young sporophyte) . that has developed from the oospore.—After Baillon. There are many other differ- from the peculiar character of their embryos. In one division the root is developed at one end of the embryo and the single cotyledon at the other end, the stem coming out on one side. In the other division the root is developed at one end of the embryo and the stem at the other end, two cotyle- dons coming out on oppo- site sides just be
. A text-book of botany for secondary schools. Botany. ANGIOSPEBMS 237. Fig. 228.—Seed of violet, one figure ahow- ing the hard testa, the other the em- bryo (young sporophyte) . that has developed from the oospore.—After Baillon. There are many other differ- from the peculiar character of their embryos. In one division the root is developed at one end of the embryo and the single cotyledon at the other end, the stem coming out on one side. In the other division the root is developed at one end of the embryo and the stem at the other end, two cotyle- dons coming out on oppo- site sides just behind the stem tip. Therefore, the first division is called Mono- cotyledons (one cotyledon), and the second is called Di- cotyledons (two cotyledons), ences between Monocotyledons and Dicotyledons, but this difference between the embryos has been selected to form the names. The embryos of Angiosperms differ much as to the com- pleteness of their development within the seed. In some plants the embryo is merely a mass of cells, without any organization of root, stem, or leaf. In many plants, on the other hand, the embryo becomes highly developed, showing all the principal organs and the plumule con- taining several well-organized young leaves (Chapter V). 142. Seed.—The seed is evidently an ovule (sporangium) containing a female gametophyte which has developed a new sporophyte (embryo). This complex structure is invested by the hard seed-coat, and is a protected resting condition of the plant. The seed-coat (testa) in Angiosperms is exceedingly variable in structure and appearance. Sometimes it is smooth and glistening, sometimes pitted, sometimes rough with warts or ridges. In many cases prominent append-. 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 Coulter, John Merle, 1851-1928. New York, D. Apple
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