. The algae. Algae. EUPHYCOPHYTA 109 jacent cells fuse, the contents of one cell passing through a pore in the intervening cell wall. The last phase to be described is that of zygotic contraction which is brought on by further action of the contractile vacuoles, after which a thick three-layered wall develops around the Fig. 61 Zygogonium ericetorum. A Zygnema stellinum, cell and nucleus before division ( x 500). B, the same, after division ( X500). C, Zygogonium^ stages in conjugation. m=male nucleus, p = conjugation process. D, terrestrial form ( x 1065). E, aplano- spores formed fr
. The algae. Algae. EUPHYCOPHYTA 109 jacent cells fuse, the contents of one cell passing through a pore in the intervening cell wall. The last phase to be described is that of zygotic contraction which is brought on by further action of the contractile vacuoles, after which a thick three-layered wall develops around the Fig. 61 Zygogonium ericetorum. A Zygnema stellinum, cell and nucleus before division ( x 500). B, the same, after division ( X500). C, Zygogonium^ stages in conjugation. m=male nucleus, p = conjugation process. D, terrestrial form ( x 1065). E, aplano- spores formed from drying up of filament ( x 542). (A, B, after Cholnoky; C-E, after Fritsch.) the middle layer or mesospore frequently being highly sculptured. The zygospore occasionally germinates almost at once, thus pro- ducing plants that account for the autumn maximum, but it is usually dormant until the following spring. Meiosis takes place when the zygote germinates and four nuclei are formed of which three abort, the plants thus only exhibiting the haploid generation. A two-celled germUng is formed, the lower cell being relatively. 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 Chapman, V. J. (Valentine Jackson), 1910-. London, Macmillan; New York, St. Martin's Press
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Keywords: ., bo, bookcentury1900, bookcollectionbiodiversity, booksubjectalgae
