Elementary botany . is the vegetative cell of the prothallium, while the smaller one, since it later forms the sperm cells, is the generative cell. This generative cell then corresponds to the central cell of the antheridium, and the vegetative cell perhaps corresponds to a wall F- cell of the antheridium. If this is so, then the Germinating spores male prothallium of angiosperms has become (P°J]en grams) of pel-r & r tandra; generative reduced to a very simple antheridium. The nucleus in one undi-r ., ,, , , , ~ r ,.,. ,. vided, in other divided farther growth takes place alter fertilization,
Elementary botany . is the vegetative cell of the prothallium, while the smaller one, since it later forms the sperm cells, is the generative cell. This generative cell then corresponds to the central cell of the antheridium, and the vegetative cell perhaps corresponds to a wall F- cell of the antheridium. If this is so, then the Germinating spores male prothallium of angiosperms has become (P°J]en grams) of pel-r & r tandra; generative reduced to a very simple antheridium. The nucleus in one undi-r ., ,, , , , ~ r ,.,. ,. vided, in other divided farther growth takes place alter fertilization, to form the two sperm In some plants the generative cell divides into nuclei. 5 vegetative nu-r & cleus m each near the the two sperm cells at the maturity of the pollen grain. pollen grain. In other cases the generative cell divides in the pollen tube after the germination of the pollen grain. For study of the pollen tube the pollen may be germinated in a weak solution of sugar, or on the cut surface 325. 326 MORPHOLOG Y. of pear fruit, the latter being kept in a moist chamber to prevent dryingthe surface. 652. In the spring after flowering the pollen escapes from the anther sacs,and as a result of pollination is brought to rest on the stigma of the it germinates, as we say, that is, it develops a long tube which makesits way down through thestyle, and in through themicropyle to the embryo sac,where, in accordance withwhat takes place in otherplants examined, one of thesperm cells unites with theegg, and fertilization of theegg is the result. 653. Macrospore and embryo sac. three carpels are united into one,two carpels are also united into oneSimple pistils are found in manyin the ranunculaceae, the buttercups,These simple pistils bear a greater
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Keywords: ., bookauthoratk, bookcentury1900, bookdecade1900, booksubjectbotany
