. Plants; a text-book of botany. Botany. Fig. 11. Vaucheria sesnlis, a Siphon form, show- ing a portion of the ccBnocytic body, an an- theridial branch (A) with an empty anthe- ridiiim (a) at its tip, and an oogonium (B) containing an oospore (c) and showing the opening (/) through which the sperms passed to reach the egg.— develops a perforated break for the entrance of the sperms, and organizes within itself a single large egg (Fig. 11, B). The an- theridium is a much smaller cell, within which numerous very small sperms are formed (Fig. 11, A, a). The sperms are discharged, swarm
. Plants; a text-book of botany. Botany. Fig. 11. Vaucheria sesnlis, a Siphon form, show- ing a portion of the ccBnocytic body, an an- theridial branch (A) with an empty anthe- ridiiim (a) at its tip, and an oogonium (B) containing an oospore (c) and showing the opening (/) through which the sperms passed to reach the egg.— develops a perforated break for the entrance of the sperms, and organizes within itself a single large egg (Fig. 11, B). The an- theridium is a much smaller cell, within which numerous very small sperms are formed (Fig. 11, A, a). The sperms are discharged, swarm about the oogonium, and finally one passes through the break and fuses with the egg, the result be- ing an oospore. The oospore or- ganizes a thick wall and becomes a resting spore. It is evident that Vaucheria is heterogamous, but all the other Siphon forms are isogamous, of which Botrijdium may be taken as an illustration (Fig. 12). 20. Spirogyra.—This is one of the commonest of the " pond scums," occurring in slippery and often frothy masses of delicate filaments fioating in still water or about Fig. 13. Botrydium, one of the Siphon forms of green algse, the whole body containing one continuous cavity, with a bulbous, chlorophyll-con- taining portion, and root- like branches which pene- trate the mud in which the plant grows. — Cald- 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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