File:The structure and development of the mosses and ferns (Archegoniatae) (1895) (14774999411).jpg

Identifier: structuredevelop00camp (find matches)
Title: The structure & development of the mosses and ferns (Archegoniatae)
Year: 1895 (1890s)
Authors: Campbell, Douglas Houghton, 1859-1953
Subjects:
Publisher: London, Macmillan
Contributing Library: The LuEsther T Mertz Library, the New York Botanical Garden
Digitizing Sponsor: The LuEsther T Mertz Library, the New York Botanical Garden

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insensibly into the stout petiole whose fleshy base forms asheath about the next younger leaf Corresponding to eachleaf is a thick unbranched root, which penetrates into thecrevices of the bark and holds the plant secure. These rootsare smooth, and show no trace of rhizoids. The petiole iscontinued up into the lamina as a very broad and thickmidrib, which in the sporiferous leaves (sporophylls) iscontinued into the peculiar elongated spike which bears thesporangia. The petiole if cut across shows a number of vascularbundles arranged in a single row, nearly concentric with theperiphery of the section. As these enter the lamina theyanastomose and form a network with elongated meshes (Fig.114, C) and no free ends. Sections of the spike cut parallelto its broad diameter show a somewhat similar arrangement ofthe vascular bundles, but here there are free branches extendingbetween the sporangia. The relations of the bundles of thefertile and sterile parts of the leaf are best followed in the
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Fig. 112.—Ophioglossuni pendithiin (L.). A, Leaf with sporangiophore, natural size; B, cross-section of the petiole, x6 ; C, section of the sporangiophore, parallel to its broad surface x6. 230 MOSSES AND FERNS CHAP. smaller species. Prantl ^ describes it as follows for O. Lusitani-cuin, and states that it is essentially the same in other species. The primary bundle given off from the stem branches just after it enters the petiole. The L > ;J /, m main bundle gives offtwo smaller lateralbranches right and left.The latter branch againnear the base of the spor-angiophore, and the upperbranches from each uniteto form the single bundlethat enters the latter. The sporangia arelarge cavities sunk in thetissue of the sporophyll,and scarcely projectingat all above the surface,where the position of eachone is indicated by afaint transverse furrowwhich marks the placewhere it opens. Seen insections parallel to the flatsurface these appear per-fectly round, but in trans-verse section are ki

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