. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. XI LEPTOSPORANGIATJE HETEROSPORE^ 399 and a smaller number of cilia than is usually the case in the Filicineje (Fig. 233, G). In Asolla the contents of the ungerminated microspore, whose wall is thin and smooth, contain but little granular mat- ter. The first indication of germination is the rupturing of the exospore along the three radiating ventral ridges, and the protrusion of a small papilla. This is cut off by a transverse wall near the top of the spore cavity, and forms at once the mothe
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. XI LEPTOSPORANGIATJE HETEROSPORE^ 399 and a smaller number of cilia than is usually the case in the Filicineje (Fig. 233, G). In Asolla the contents of the ungerminated microspore, whose wall is thin and smooth, contain but little granular mat- ter. The first indication of germination is the rupturing of the exospore along the three radiating ventral ridges, and the protrusion of a small papilla. This is cut off by a transverse wall near the top of the spore cavity, and forms at once the mother cell of the single antheridium (Fig. 234, C). Belajeff. Fig. 234.—Azolla Uliculoides. A, Massula with enclosed microspores {sp), X2S0; gU glochidia; B-D, development of male prothallium and antheridium, X560; o, oper- cular cell; E, cross-sections of a ripe antheridium, X750; i, the top; 2, nearly median section; x, second prothallial cell. ((3), p. 329) says the next divisions are nearly parallel and divide the antheridium into three cells, one above the other, and of these only the middle ones divide further. For some reason, which is not quite clear from his account, Belajeff does not re- gard the whole upper cell as an antheridium, but says that the latter is only formed after five vegetative cells have been cut off. It seems much more in accordance with the structure found in the related homosporous Ferns to regard the whole. 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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