. A textbook of botany for colleges and universities ... Botany. Figs. 412—414. — Male gametoph3^e of Marsilea: 412, first division of the microspore into vegetative cell (the smaller) and antheridium initial; 413, first division of an- theridium initial; 414, antheridium with wall of sterile cells investing spermatogenous cells (shaded). — After Campbell. the sporocarp is an indusium investing a sorus, while in Marsileaceae it is a leaf blade inclosing a group of sori with their indusia. Gametophytes. —The male gametophyte does not emerge from the microspore, as it does in Salviniaceae, remai
. A textbook of botany for colleges and universities ... Botany. Figs. 412—414. — Male gametoph3^e of Marsilea: 412, first division of the microspore into vegetative cell (the smaller) and antheridium initial; 413, first division of an- theridium initial; 414, antheridium with wall of sterile cells investing spermatogenous cells (shaded). — After Campbell. the sporocarp is an indusium investing a sorus, while in Marsileaceae it is a leaf blade inclosing a group of sori with their indusia. Gametophytes. —The male gametophyte does not emerge from the microspore, as it does in Salviniaceae, remaining entirely within the spore coat, as in Sdaginella and Isoetes. As in all the pre%iously mentioned cases of heterospory, a single vegetative cell and a single antheridium make up the male gametophyte (figs. 412-414); but in Marsile- aceae the output of sperms is 32, much larger than in Salviniaceae (8) and in Isoetes (4). The sperms of Marsilea are remarkable for the great number of coils in the beak, reaching 13 or 14, the upper 12 or 13 having no cilia (fig. 415). The female gametophyte closely resembles that of the Salviniaceae, and the nucleus of the great nutritive cell remains undivided, as in Salvinia (figs. 416, 417). Embryo. —The embryo develops as in all the leptosporangiate ferns, the first wall of the egg being vertical (parallel with the long axis of the archegonium), and the four body regions being differentiated at the quad- rant stage. It is noteworthy that the Marsileaceae have retained the primary vertical wall of the egg, characteristic of the leptosporangiate. 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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