. Botany for high schools and colleges. Botany. 300 BOTANY. 398.—Until Stahl's researches* showed the existence of sexual organs in Collema, they were entirely unknown among lichens. He discovered, deeply imbedded in the tissue of the plant, an organ composed of a spirally coiled hypha-branch, and a vertical septate portion, which rises to, and projects above, the surface; the spirally coiled por- tion he called the ascogonium, and the vertical portion the tri- chogyne. The whole he regarded as a species of carpogonium (Fig. smail portion of the thallus of Col^ nnry a „ „y,A J\ "pfp rvTio
. Botany for high schools and colleges. Botany. 300 BOTANY. 398.—Until Stahl's researches* showed the existence of sexual organs in Collema, they were entirely unknown among lichens. He discovered, deeply imbedded in the tissue of the plant, an organ composed of a spirally coiled hypha-branch, and a vertical septate portion, which rises to, and projects above, the surface; the spirally coiled por- tion he called the ascogonium, and the vertical portion the tri- chogyne. The whole he regarded as a species of carpogonium (Fig. smail portion of the thallus of Col^ nnry a „ „y,A J\ "pfp rvTioorvorl lema Jacobctfolium, showing the '**J') ^' '^J ^^^ "')• ^^ OOServea '^°hx^the 'Soc ile^" onidta^and^a spcrmatia adhering to the pro- —: =..._,. ....,=.v _i .---l:-.^ portion of the tricho- some of these united them-. S06.—Vertical section of epermagoniuin, from which eperma- jectinff tia are escaping. Magnified.—^After ^ ° Tulasne. gjne : selves to the trichogyne by means of a tube (C, Fig. 207). The result of this coalescence was the withering and disap- pearance of the cells of the tricho- gyne, and the growth and devel- opment of the as- cogonium. The latter process takes place as follows: " The cells of the ascogonium first of all increase in size, and then undergo division ; as a re- sult of this, the sniral ai-TaTio-Qw>Qv,+ ^' coalescence of a spermatiiim, S, wi( bpirai arrangement a11 the figures magnified, B and (7 much of the cells be- -^^st*"- comes less and less conspicuous, for the cells gradually sepa- * " Ueber die Qesclilechtliclie Fortpflanzung der Collemaceen," 1877 (On the Sexual Organs of the Collerancea;). A brief synopsis of Stahl's results appeared in the Qr. Jour, of Mic. Science, October, 1878,. 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
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1885
