The structure & development of the mosses and ferns (Archegoniatae) . Fig. 83.—A, B, Germinating spores oi A. ^eirojihila, X 200 ; C, protonema with bud {k) ; D. youngarchegonium in optical section ; E, i, 2, two views of a very young embryo of A. crassmerva,X 266 ; F, somewhat older embryo of ^. petrophila ; G, older embryo showing the first archesporialcells; H, I, cross-sections of young embryos, X 200. A-D, after Kiihn ; E-I, after Waldner. germinate within a week, or sometimes remain unchanged formonths. They have a thick dark-brown exospore and containchlorophyll and oil. The first divis

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The structure & development of the mosses and ferns (Archegoniatae) . Fig. 83.—A, B, Germinating spores oi A. ^eirojihila, X 200 ; C, protonema with bud {k) ; D. youngarchegonium in optical section ; E, i, 2, two views of a very young embryo of A. crassmerva,X 266 ; F, somewhat older embryo of ^. petrophila ; G, older embryo showing the first archesporialcells; H, I, cross-sections of young embryos, X 200. A-D, after Kiihn ; E-I, after Waldner. germinate within a week, or sometimes remain unchanged formonths. They have a thick dark-brown exospore and containchlorophyll and oil. The first divisions take place before theexospore is ruptured, and may be in three planes, so that theyoung protonema then has the form of a globular cell mass(Fig. 83, A). This stage recalls the corresponding one inmany of the thallose Hepaticae, Peliia, Radtda, and isentirely different from the direct formation of the filamentousprotonema of most Mosses. Some of the superficial cells ofthis primary tubercle grow out into slender filaments, eitherwith straight or oblique

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Keywords: ., bookcentury1800, bookdecade1890, bookidstructuredev, bookyear1895