. Botany of the living plant. Botany; Plants. DROWN ALGAE 387 its attractive influence on their movements (Fig. 287, 5). But only one penetrates each egg, and its nucleus has been followed on its course through the cytoplasm till it fuses with the nucleus of the ovum (Fig. 287, 6). The rest at once move away, as though a repellent influence from the egg had replaced the previous attraction. The immediate consequence of fertilisation is the deposit of a cell-wall covering the zygote. It settles on some solid substratum,. Fig. 289. Drawings direct from successively older plants of Fucus s
. Botany of the living plant. Botany; Plants. DROWN ALGAE 387 its attractive influence on their movements (Fig. 287, 5). But only one penetrates each egg, and its nucleus has been followed on its course through the cytoplasm till it fuses with the nucleus of the ovum (Fig. 287, 6). The rest at once move away, as though a repellent influence from the egg had replaced the previous attraction. The immediate consequence of fertilisation is the deposit of a cell-wall covering the zygote. It settles on some solid substratum,. Fig. 289. Drawings direct from successively older plants of Fucus serratus, showing the regular dichotomy. and germinates directly into a new Fucus plant. Stones on a rocky shore where Fucoids grow may be found in summer covered by a dense growth of myriads of these young plants (Fig. 289). In the life-history of Fucus the increase in numbers is exclusively through the sexual process. There is no production of zoospores, nor any non-sexual propagation, as there is in the simpler Brown Seaweeds. The Fucus plant is diploid and reduction takes place in the first divisions respectively of the antheridial and oogonial cells. The haploid phase is extremely brief and there is, strictly speaking, no alternation of generations as in Laminaria. By com- parison with the very reduced gametophyte of Laminaria, it has been suggested. 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 Bower, F. O. (Frederick Orpen), 1855-1948; Wardlaw, C. W. (Claude Wilson), 1901-. London, Macmillan and Co. , ltd.
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