. A textbook of botany for colleges and universities ... Botany. THALLOPHYTES 43 posed of eight triangular, platelike cells known as shields (fig. 115). Projecting centripetally from the center of each shield is an elongated cell {manubrium), which bears a terminal cell {head cell). These head cells give rise to a varying number of similar cells, and each ultimate cell produces a pair of long filaments, each consisting of approximately 200 cells, each cell producing a single sperm (figs. 117, 118). The in- terior of the antheridium, therefore, is a tangle of filaments, and the. Figs. 115-119.
. A textbook of botany for colleges and universities ... Botany. THALLOPHYTES 43 posed of eight triangular, platelike cells known as shields (fig. 115). Projecting centripetally from the center of each shield is an elongated cell {manubrium), which bears a terminal cell {head cell). These head cells give rise to a varying number of similar cells, and each ultimate cell produces a pair of long filaments, each consisting of approximately 200 cells, each cell producing a single sperm (figs. 117, 118). The in- terior of the antheridium, therefore, is a tangle of filaments, and the. Figs. 115-119. — Chara; 115, branch bearing oogonium (showing its sterile jacket and crown) and antheridium (showing its interlocking, shieldlike wall cells); ii6, young oogonium (stalked and not yet completely invested by the jacket) and antheridium; 117, manubrium bearing head cells and sperm-containing filaments; ii8, detail of cells of filament showing contained sperms; 119, sperms (spirally coiled and biciliate).— After Sachs. sperm output of a single antheridium may range between 20,000 and 50,000. The sperm is a more specialized structure than is the zoospore- jike sperm of the ordinary algae, and more resembles the sperms of higher plants. The nucleus with its sheath of cytoplasm forms the body ; the cytoplasm extends to form an elongated more or less spirally coiled beak, and from its tip two long ciha are produced (fig. 119). Oogonium. —The oogonium, which replaces a secondary branch, is an enlarged apical cell, and produces a single large egg filled with starch. 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; Barnes, Charles Reid, 1858-1910, joint author; Cowles, Henry Chandler, 1869- joint author. New York, Cincinnati [etc] American book company
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