. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. 320 MOSSES AND FERNS lirBuller also showed that the starch which is usually present in "the vesicle of the spermatozoid, when it escapes from the antheridium, disappears completely in species where the period "of -activity is prolonged. Thus in Gymnogramme Mertensii, â¢the swarm-period lasted about two hours, and during this time the starch disappeared completely. Fertilisation i Shaw (2) has made a careful study of the fertilisation in Struthioptcris and in Onoclea. He states that b
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. 320 MOSSES AND FERNS lirBuller also showed that the starch which is usually present in "the vesicle of the spermatozoid, when it escapes from the antheridium, disappears completely in species where the period "of -activity is prolonged. Thus in Gymnogramme Mertensii, â¢the swarm-period lasted about two hours, and during this time the starch disappeared completely. Fertilisation i Shaw (2) has made a careful study of the fertilisation in Struthioptcris and in Onoclea. He states that before the arche-. FlG. 177.â^A, Ostnunda cinnamomea, section of a recently fertilised archegonium, X450. A spermatozoid has penetrated the nucleus of the egg, and several are in the space above the egg. B, Onoclea sensibilis. Egg fourteen hours after the penetration oi the spermatozoid, which is still recognizable within the egg nucleus, X900. (B, after Shaw.) gonium opens, the egg is depressed above, and the nucleus flattened. As soon as the archegonium opens, and the dis- organised contents of the neck cells are expelled, the egg â becomes turgid, and the depressed upper part forms the recep- tive spot. (Fig. 177.) The mucilaginous matter ejected from the archegonium retards the movements of the spermatozoids, and detaches the vesicle. As the spermatozoid penetrates the neck, it becomes much stretched out, and forces its way through to the central cavity of the archegonium, by a slow screw-like movement. Having penetrated into the ventral cavity, the coils draw together again, and the movements are much more rapid. After a spermatozoid has entered the tgg at the receptive. 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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