. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. VII PTERIDOPHYTA—FILICINE^—OPHIOGLOSSACE^ 241 the thallus. The basal cell also divides more extensively, but the group of cells derived from it is easily recognisable in the ripe archegonium. The central cell divides transversely, the lower cell forming the egg, and the ventral canal cell, the upper one giving rise to the single neck canal cell, whose nucleus later divides as in Ophioglossum. The mature egg cell contains dense cytoplasm, but has a vacuole within it. Jeffrey observed a spermato
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. VII PTERIDOPHYTA—FILICINE^—OPHIOGLOSSACE^ 241 the thallus. The basal cell also divides more extensively, but the group of cells derived from it is easily recognisable in the ripe archegonium. The central cell divides transversely, the lower cell forming the egg, and the ventral canal cell, the upper one giving rise to the single neck canal cell, whose nucleus later divides as in Ophioglossum. The mature egg cell contains dense cytoplasm, but has a vacuole within it. Jeffrey observed a spermatozoid in the act of penetrating the egg, which showed an extension toward the entering spermatozoid. The details of fertilisation, however,. Fig. 129.—Batrychium Virginianum. Development of the archegonium, X about 450. were not made out, but they probably correspond closely with those observed in other Ferns. Helmin thostachys The gametophyte of Helminthostachys (Lang (4)), the third genus of the Ophioglossacese, does not differ essentially from the other genera, being also subterranean. It is nearly cylindrical in form (Fig. 126, C). The lower part, which is brown, and covered with rhizoids, is sterile, and contains an 16. 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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