. Comparative anatomy of the vegetative organs of the phanerogams and ferns;. Plant anatomy; Ferns. STRUCTURE OF RADIAL BUNDLES. 3^3 tracheides, which forth several rows, are of a different structure, similar to that described in the case of the stem and leaf at p. 346, and are all of approximately equal and relatively small width. Triarch and tetrarch bundles sometimes occur in thick roots of species, which are usually diarch; triarch-bundles have been observed in Pilularia, Equisetum, Botrychium, Blechnum brasiliense, and Cyathea meduUaris, tetrarch in Equisetum, the Blechnum above mentioned
. Comparative anatomy of the vegetative organs of the phanerogams and ferns;. Plant anatomy; Ferns. STRUCTURE OF RADIAL BUNDLES. 3^3 tracheides, which forth several rows, are of a different structure, similar to that described in the case of the stem and leaf at p. 346, and are all of approximately equal and relatively small width. Triarch and tetrarch bundles sometimes occur in thick roots of species, which are usually diarch; triarch-bundles have been observed in Pilularia, Equisetum, Botrychium, Blechnum brasiliense, and Cyathea meduUaris, tetrarch in Equisetum, the Blechnum above mentioned, and Cyathea. In the species of Trichomanes^ investigated,triarch to octarch bundles usually occur, diarch bundles being rare, while, on the other hand, the latter are characteristic of the roots of Hymeno- phyllum. On the monarch bundles of some species of Trichomanes, see FIG. 169.—Adiantum Moritzianmn (225), Old root, cross-section. A—A hairs of the epidermis cut through, ti endodermis /c pericainbium, /r primitive tracheides of the diarch xylem aJtemating with two phloem groups. The xylem-plates are in most cases united in the middle, in the thinner bundles often by means of a very large vessel (e. g. Equisetum), or of a row consisting of two large vessels, crossing the diametral pair of plates at right angles (Fig. 169). In other respects various subordinate differences of form occur, e. g. a regularly elliptical cross-section of the diametrally united plate in Osmunda, Todea, &c., &c. The arrangement of the phloem-groups corresponds to the general plan of ' Mettenius, Hymenophyllaceen, /. c. p, 420.—Russow, /; c. p. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bary, A. de (Anton), 1831-1888; Bower, F. O. (Frederick Orpen), 1855-1948; Scott, Dukinfield Henry, 1854-1934. Ox
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Keywords: ., bookcentury1800, bookdecad, booksubjectplantanatomy, bookyear1884
