. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. S6 MOSSES AND FERNS but there is a rapid lateral growth with results in the formation of two valves, which meet in front much like the two parts of a bivalve shall, and this involucre completely encloses the devel- oping sporogonium. In the simplest cases, where the archegonia are borne upon a receptacle^ which is raised upon a stalk, , Plagiochasma, Clevea (Fig. 20, A), the receptacle does not represent, accord- ing to Leitgeb ((7), vi., p. 29), a complete branch, but is only a dorsal out
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. S6 MOSSES AND FERNS but there is a rapid lateral growth with results in the formation of two valves, which meet in front much like the two parts of a bivalve shall, and this involucre completely encloses the devel- oping sporogonium. In the simplest cases, where the archegonia are borne upon a receptacle^ which is raised upon a stalk, , Plagiochasma, Clevea (Fig. 20, A), the receptacle does not represent, accord- ing to Leitgeb ((7), vi., p. 29), a complete branch, but is only a dorsal outgrowth of the latter, which may grow out beyond it, or even form several receptacles in succession. The first indi- cation of the recep- , V. 9. D. tacle is a dorsal prom- inence which soon be- comes almost hemi- spherical, and near the hinder margin the first archegonium arises, without, apparently, any special relation to the growing point. â On the lateral margins are then formed two other archegonia, not, however, simultane- ously; and finally a fourth may be formed in front: three or four archegonia in all seem to be the ordinary number. The stalk of the receptacle is also a dorsal appendage of the thallus, and not a direct continuation of it. The next type is that which Leitgeb attributes to Grimaldia, Reboulia, Fimbriaria, and some others, but it is not the type found in Fimbriaria Californica. In this type the structure of. 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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