The structure & development of the mosses and ferns (Archegoniatae) . -?•), X4- goes the usual divisions. Of the three peripheral cells one ismuch smaller and does not as a rule divide longitudinally, sothat the neck has normally but five rows of cells instead of six, asin the Marchantiaceae. Owing to the formation of the pedicel,. Fig. 39.—A, Vertical, B, C, horizontal sections through the apex of Pallavicinia cylmdrica (Aust.),.r, apical cell, A, X225; B, C, X450; D, E, Pellia epiphylla (Nees); D, vertical section; E,horizontal (optical) section, X450. MOSSES AND FERNS CHAP. the archegonium
The structure & development of the mosses and ferns (Archegoniatae) . -?•), X4- goes the usual divisions. Of the three peripheral cells one ismuch smaller and does not as a rule divide longitudinally, sothat the neck has normally but five rows of cells instead of six, asin the Marchantiaceae. Owing to the formation of the pedicel,. Fig. 39.—A, Vertical, B, C, horizontal sections through the apex of Pallavicinia cylmdrica (Aust.),.r, apical cell, A, X225; B, C, X450; D, E, Pellia epiphylla (Nees); D, vertical section; E,horizontal (optical) section, X450. MOSSES AND FERNS CHAP. the archegonium is quite free at the base, and like that ofAneura the wall of the venter is two-layered. The neckbecomes very long, and, according to Janczewski, the number ofneck canal cells may reach sixteen or even eighteen. The antheridia of Pellia are larger than in Aneura, but intheir development are similar except that the stalk is multi-cellular. The spermatozoidsare the largest known amongthe Hepaticai (Fig. 35, D, E).In some species of Palla-vicinia the very strongly de-veloped midrib is made upin part of thick-walled elon-gated cells, but usually suchcells are absent. The develop-ment of the sporogoniumis best known in Pellia epi-phylla} Here the first wall,as in Aneura, separates alower cell, which simply formsan appendage, f
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Keywords: ., bookcentury1800, bookdecade1890, bookidstructuredev, bookyear1895
