. A text-book of botany for secondary schools. Botany. 112 A TEXT-BOOK OP BOTANY Vaucheria produces very large asexual spores. The tip of a branch becomes separated from the rest of the body by a wall (Fig. 101, A). In this improvised chamber the whole of the contents form a single large spore. It escapes into the water through an opening in the wall, (Fig. 101, B) and finally develops a new filament (Fig. 101, C). Sex organs (antheridia and oogonia) are also developed. In a common form of Vaucheria they appear separately on the side of the large ccenocytic body, and are separated from the gen
. A text-book of botany for secondary schools. Botany. 112 A TEXT-BOOK OP BOTANY Vaucheria produces very large asexual spores. The tip of a branch becomes separated from the rest of the body by a wall (Fig. 101, A). In this improvised chamber the whole of the contents form a single large spore. It escapes into the water through an opening in the wall, (Fig. 101, B) and finally develops a new filament (Fig. 101, C). Sex organs (antheridia and oogonia) are also developed. In a common form of Vaucheria they appear separately on the side of the large ccenocytic body, and are separated from the general cavity by walls. The oogonium is a globular cell (Fig. 102, b), usually with a perforated beak for the entrance of sperms (Fig. 102, /), and contains a single. Fig. 102.—Sexual reproduction in Vaucheria: A, a single antheridial branch with an empty antheridium (a) at its tip, and also an oogonium (5) containing a heavy-walled oospore (c) and showing the beak (/) through which the sperm passed; B, another species, in which a single branch bears several oogonia, and a terminal coiled antheridium. large egg. The antheridium is a much smaller cell, on the end of a branch (Fig. 102, a), within which numerous very small sperms are formed. The usual escape into the water and entrance into the oogonium is followed by fertilization (one sperm fusing with the egg), which results in an oospore. The oospore develops a thick wall and is thus protected until the next growing season (Fig. 102, c). In another 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
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