Introduction to structural and systematic botany, and vegetable physiology, : being a 5th and revedof the Botanical text-book, illustrated with over thirteen hundred woodcuts . e, be-comes a new cell or spore, in due time germinating into a iicav plant. 657. In reproduction by conjugation, the two cells or individualsconcerned are alike; one is as much the fertilizer or the fertilizedas the other. But the clear distinction of sexes which all the higherCryptogamous no less than Phasnogamous plants exhibit, is also mani-fested in those of the simplest structure, viz. in plants consisting ofsingl
Introduction to structural and systematic botany, and vegetable physiology, : being a 5th and revedof the Botanical text-book, illustrated with over thirteen hundred woodcuts . e, be-comes a new cell or spore, in due time germinating into a iicav plant. 657. In reproduction by conjugation, the two cells or individualsconcerned are alike; one is as much the fertilizer or the fertilizedas the other. But the clear distinction of sexes which all the higherCryptogamous no less than Phasnogamous plants exhibit, is also mani-fested in those of the simplest structure, viz. in plants consisting ofsingle cells, or of rows or clusters of similar and essentially inde-pendent cells. That is, even these afford examples of FIO. 635. Magnified view of two conjugating filaments of Zygnema, showing all the stagesof the process by which the cells from two filaments form each a corresponding protuberance,these come into contact, the intervening walls are absorbed, and the contents pass from onecell into the other, condense, acquire an investing membrane, and so form a spore : the stagesare represented from above downwards ; a completed spore is seen at the bottom, on the 334 REPRODUCTION IN 658. Direct Fertilization of Spores by Spermatozoids from an Anthc- lidium; the latter answering to the anther, or essential part of thestamen, of Phsenogamous plants. Colin * has shown that evenVolvox — an undoubted vegetable, consisting of microscopic one-celled plants of rounded form, grouped into a spherical colony — hasa true sexual propagation, like that of the higher green Alga?, someof the individuals or cells of the sphere producing antheridia or fer-tilizing cells, while others produce spores, or bodies which becomesuch on being fertilized by the antheridia, which alone renders themcapable of germination. A good general idea of bisexual reproductionin the simplest Algaj may best be obtained from a brief abstract ofAvhat has lately been discovered by Pringsheim and Cohn in two o
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Keywords: ., bookauthorgra, bookcentury1800, bookdecade1860, booksubjectbotany
