. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. The Ferns and Their Allies 289 When mature, the pro- thallus produces egg cells and sperms m small organs on Its under surface. The sperms are small and swim actively, and they reach the egg cells when the thallus is wet. The sperm tinites with the egg and forms an oospore. The formation of the oospore completes the life of this, the sexual, gen- eration of the fern. The oospore germinates while still attached to the httle prothallus, and from it develops the large fern plant with w
. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. The Ferns and Their Allies 289 When mature, the pro- thallus produces egg cells and sperms m small organs on Its under surface. The sperms are small and swim actively, and they reach the egg cells when the thallus is wet. The sperm tinites with the egg and forms an oospore. The formation of the oospore completes the life of this, the sexual, gen- eration of the fern. The oospore germinates while still attached to the httle prothallus, and from it develops the large fern plant with which we are famihar. This second gen- eration has true roots, stems, and leaves, and on the lower side of the leaves great numbers of sporangia are produced. These Ue in groups which may be seen with the naked eye as brown dots. Within the sporangia asexual spores are formed, and because asexual spores are produced by this generation, it may be called the asexual generation of the plant. The ferns, therefore, do not reproduce themselves directly. The plants with the large, feathery leaves that we know as. Fig. 171. Underground stem, roots, and leaves of 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
