. The structure and development of mosses and ferns (Archegoniatae). temof Ophioglossiim vulgatumshows considerable variation,and may be either a three orfour-sided prism, i. e., it ap-^ ,. , , , . ,, parently also may have the riG. 133.—Ophioglossuni pendulum. A, Me- | -^ > / \ dian longitudinal section of stem apex, X4; uaSC trUnCatC. JriOlle S \^ )^, the growing point; B, young sporophyll, ^gg^^jQj^ ag-rCCS with thisX2; sp, the sporangiophore; C, an older - ^ leaf, showing the venation, X2. CXCCpt that he StatCS that he always found the cell pointedbelow, not truncate. The segments cu
. The structure and development of mosses and ferns (Archegoniatae). temof Ophioglossiim vulgatumshows considerable variation,and may be either a three orfour-sided prism, i. e., it ap-^ ,. , , , . ,, parently also may have the riG. 133.—Ophioglossuni pendulum. A, Me- | -^ > / \ dian longitudinal section of stem apex, X4; uaSC trUnCatC. JriOlle S \^ )^, the growing point; B, young sporophyll, ^gg^^jQj^ ag-rCCS with thisX2; sp, the sporangiophore; C, an older - ^ leaf, showing the venation, X2. CXCCpt that he StatCS that he always found the cell pointedbelow, not truncate. The segments cut off from the lateralfaces are large, and the divisions irregular. They are appar-ently formed in very slow succession, and the irregularity of thesucceeding divisions in the segments themselves soon makes itimpossible to trace their limits. Each segment apparently givesrise to a leaf, but this is impossible to determine with first wall in the young segment probably divides it into aninner and outer cell, but the next divisions could not be deter-. VII PTERIDOPHYTA—FILICINEJE—OPHIOGLOSSACEJE 249 mined positively. Probably, as in Botrychium, the outer cell isnext divided by a vertical wall, ])erpendicular to the broadfaces of the segment, into two cells, in which divisions thentake place in both transverse and longitudinal direction withoutstrict regularity. The stem in O. pendulum is mostly made up of thin-wallcdparenchyma, and the vascular bundles are much less developedthan is the case in the underground stem of O. vulgatiim orBotrychium. The bundles are of the collateral form, /. c, theinner side is occupied by the xylem, the outer by the phloem,
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Keywords: ., bookauthorcampbelldouglashought, bookcentury1900, bookdecade1910
