. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. Fig. 241.—A, Young microsporangial sorus of A. Uliculoides, X80; col, columella; id, indusium; B, nearly ripe microsporangium, X225. not become absorbed, as Strasburger ((6), p. 71) states, but remains intact, though very much compressed, until the spore is ripe. The sporocarps of Salvinia are like those of Azolla, but the two layers of cells are separated by a series of longitudinal air- spaces which correspond to ridges upon the surface of the sporo- carp (Fig. 233, D). The microsporangia of
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. Fig. 241.—A, Young microsporangial sorus of A. Uliculoides, X80; col, columella; id, indusium; B, nearly ripe microsporangium, X225. not become absorbed, as Strasburger ((6), p. 71) states, but remains intact, though very much compressed, until the spore is ripe. The sporocarps of Salvinia are like those of Azolla, but the two layers of cells are separated by a series of longitudinal air- spaces which correspond to ridges upon the surface of the sporo- carp (Fig. 233, D). The microsporangia of Azolla have a long stalk, which is composed of usually two, but sometimes three rows of cells. The sixteen sporogenous cells all develop, so that there are normally sixty-four microspores in each sporangium. These have the exospore thin and smooth, and are included in a kind of common epispore, which here too owes its origin mainly to the tapetal cells. This episporic substance is divided into masses (massulas), which have the foamy structure of the episporic apendages of the macrospore. This appearance is apparently due to the formation of vacuoles, which make these. 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 Campbell, Douglas Houghton, 1859-1953. New York, The Macmillan Company;
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