Guide to the Study of Common Plants, an Introduction to Botany

Guide to the Study of Common Plants, an Introduction to Botany

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1893 edition. Excerpt: ...or on different individuals. The whole structure is best studied by means of longitudinal sections, which are easily made with a razor, after a little practice, without any previous preparation of the specimen. Examining such sections under the microscope, if we chance to have selected a male specimen we shall find antheridia in great numbers growing at the apex of the axis, and with them slender, filamentous bodies, paraphyses, while outside of both is the circle of perichsetial leaves. The antheridia are sacs, usually oblong in shape, with a wall consisting of a single layer of cells, the interior being composed of the mother cells of the antherozoids. The latter are ciliated, protoplasmic bodies, closely resembling those of the ferns. In the examination of a female specimen the paraphyses are seen as before, but archegonia take the place of antheridia. A fully formed archegonium is a flask-shaped body with an elongated neck, and an enlarged ventral portion, within which is the oosphere. Fertilization takes place by the mingling of the substance of an antherozoid with that of the oosphere, after the antherozoid has forced it way down through the long canal of the neck. The fertilized oosphere, now called the oospore, becomes septate, and by still further cell-division and growth the capsule with its seta, spores, and various parts already described, is formed. With suitable material and sufficient time the student can readily verify most of the facts here given. Cycle of Development. It will be observed that in the mosses alternation of generations takes place. The sporophyte, or non-sexual generation, begins with the formation of the oospore and closes with the spore, while the oophyte, or sexual generation, begins with the germination of the...show more

Product details

  • Paperback | 64 pages
  • 189 x 246 x 3mm | 132g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236497309
  • 9781236497307