. Plant studies; an elementary botany. Botany. THE GREAT GROUPS OF ALG^ 247 spore is organized. As the gametes look alike, the process is conjuga- tion, and the sex spore is a zygote, which, with its heavy wall, is rec- ognized to be a resting sporo. At the beginning of each growing season, the well-protected zygotes which have endured the winter germinate directly into new S2)i- 7'Of/i/ra filaments. On account of this peculiar style of sexual reproduction, in which gametes are not discharged, but reach each other through sjje- cial tubes, Spirogyvd and its allies are called Conjugate forms—th
. Plant studies; an elementary botany. Botany. THE GREAT GROUPS OF ALG^ 247 spore is organized. As the gametes look alike, the process is conjuga- tion, and the sex spore is a zygote, which, with its heavy wall, is rec- ognized to be a resting sporo. At the beginning of each growing season, the well-protected zygotes which have endured the winter germinate directly into new S2)i- 7'Of/i/ra filaments. On account of this peculiar style of sexual reproduction, in which gametes are not discharged, but reach each other through sjje- cial tubes, Spirogyvd and its allies are called Conjugate forms—that is, forms whose bodies are "yoked together " during the fusion of the gametes. In some of the Conjugate forms the zygote is formed in the connect- ing tube (Fig. 215, ,1), and some- times zygotes are formed without conjugation (Fig. 215, i?). Among the Conjugate forms the Desmids are of great interest and beauty, being one-celled, the cells being organized into two distinct lialves (Fig. 216). 168. Conclusions. — The (Jreen Algfe, as indicated by the illustra- tions given above, include simple one-celled forms which reproduce by fission, but they are chiefly fila- mentous forms, simple or branching. These filamentous bodies either have the cells separated from one another 17. 215. Two Conjugate forme : A [Mougeotia), showing for- rnaMon of zygote in conjuga- ting tube; B, C {Gouafone- i/ia), sho\\'ing formation of zj-gote \:'itliout conjugation. —After 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 Coulter, John Merle, 1851-1928. New York, D. Appleton and Company
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