. Carnegie Institution of Washington publication. Fig. i-'*. Danaajamaieensis. A. Section near base of lamina of cotyledon. â 75. D. An older stoma. X200. B. Part of the lamina, ft, stoma. X200. K. Cross-section of a peltate scale, from young cotyledon. X200. C. Young stoma. In Marattia douglasii the nearly cylindrical petiole is somewhat channeled on its inner side and the single and nearly centrally placed vascular bundle appears almost circular in section. The xylem forms a somewhat crescent-shaped body, completely inclosed by the phloem, but the phloem is less developed upon the inner side
. Carnegie Institution of Washington publication. Fig. i-'*. Danaajamaieensis. A. Section near base of lamina of cotyledon. â 75. D. An older stoma. X200. B. Part of the lamina, ft, stoma. X200. K. Cross-section of a peltate scale, from young cotyledon. X200. C. Young stoma. In Marattia douglasii the nearly cylindrical petiole is somewhat channeled on its inner side and the single and nearly centrally placed vascular bundle appears almost circular in section. The xylem forms a somewhat crescent-shaped body, completely inclosed by the phloem, but the phloem is less developed upon the inner side and the bundle closely approaches the collateral type. Fannin cells occur, but are not so conspicuous as they are in Angiopteris. The lamina of the cotyledon is similar in structure to that of the latter, the leaves differing mainly in the much smaller development of the mesophyll, which is often reduced to a single layer of cells (fig. 127, B). The smaller veins have the xylem reduced to a few one to threeâsmall tracheids situated upon the upper side of the bundles, so that the bundles are strictly collateral. Stomata of the ordinary form occur upon the lower surface of the leaf and these sometimes show a series of concentrically arranged cells about them. The petiole of the cotyledon in Angiopteris resembles in sec- tion that of Marattia, but it is slightly winged (fig. 130), and the tannin cells adja- cent to the vascular bundle are more conspicuous than in Marattia. In Kaulfussia (fig. 137, C), where the petiole is stouter than in the other genera, the section is more nearly circular than in Angiopteris, but it is also slightly winged, these wings being developed almost to the proportions ol stipules at the conn acted. Fig. 130. A. Section of petiole of cotyledon of Angiopteris. X95. B. Vascular bundle. X200. The shaded cell is a tannin Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - color
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Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1910, bookyear1911
