. Comparative anatomy of the vegetative organs of the phanerogams and ferns. Plant anatomy; Phanerogams; Ferns. 368 PRIMARY ARRANGEMENT OE TISSUES. outside of the wide intercellular passage of the sympodial bundle, while two some- what smaller groups stand symmetrically right and left of the centre of its inner side. In the remaining bundles the intercellular passage or vascular group is bordered on the outside by an arched group of sieve-tubes. In the other Potamogetons investigated (lucens, gramineus, densus, crispus, pec- tinatus, and pusillus), in Zanichellia, Althenia, Cymodocea, and Zost
. Comparative anatomy of the vegetative organs of the phanerogams and ferns. Plant anatomy; Phanerogams; Ferns. 368 PRIMARY ARRANGEMENT OE TISSUES. outside of the wide intercellular passage of the sympodial bundle, while two some- what smaller groups stand symmetrically right and left of the centre of its inner side. In the remaining bundles the intercellular passage or vascular group is bordered on the outside by an arched group of sieve-tubes. In the other Potamogetons investigated (lucens, gramineus, densus, crispus, pec- tinatus, and pusillus), in Zanichellia, Althenia, Cymodocea, and Zostera, the tracheae in the node are persistent, while those in the internode are all transitory. To every bundle an intercellular passage corresponds, which is surrounded on the outsicle by phloem. Where several bundles traverse the internode, they approach each other closely in a manner similar to that described for P. natans; in the case of the two leaf-trace bundles in the internodes of P. lucens and gramineus this goes so far, that. '-^VHW^V^' FJG. 170 (145').—Potamogeton natans. Axial mass of the internode. containing the vascular bundles ; cross-section. K unilaterally thickened endodennis, containing starch; outside the latter lacunose cortical parenchyma, with abundant starch ; / air-cavities. Explanation of the numerals at p. 272. The delicate groups of tissue of the numbered circles are the phloem; the wide meshes in the latter are the sieve-tubes of the bundles ; the circles in which the numerals stand are the xylem portions, usually converted into cavities. Between the bundles is parenchyma containing starch, and sclerenchymatous fibres with a narrow lumen appearing as a darker point. their intercellular passages, which are turned towards each other, are only separated by one layer of cells, or in most cases are united to form a single passage. The single axial sympodial bundle, which (without cauline bundles) traverses the internode in the upright stem of P. pectin
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Keywords: ., bookcentury1800, bookdecad, booksubjectplantanatomy, bookyear1884
