. Critical researches on the potamogetons. . str sir vbls Fig. 87. P. repens Haoste. A, Top of a leaf, -J, showing the form and nervation. B, Young ligule, |. C, Transverse section of part of the epidermis and its strengthening layei', ''jO, ep, epidermis, lip^ pseudo-hypoderma, str, bast bundle. I), Transverse section of the central stele, \', showing the vascular bundles and the interjacent mechanic tissue. £', Transverse sect, of a leaf at the middle and, F, at the base, immediately above the insertion point, \P j »», niidvein, «', principal and n", secondary lateral nerves, sU% margin
. Critical researches on the potamogetons. . str sir vbls Fig. 87. P. repens Haoste. A, Top of a leaf, -J, showing the form and nervation. B, Young ligule, |. C, Transverse section of part of the epidermis and its strengthening layei', ''jO, ep, epidermis, lip^ pseudo-hypoderma, str, bast bundle. I), Transverse section of the central stele, \', showing the vascular bundles and the interjacent mechanic tissue. £', Transverse sect, of a leaf at the middle and, F, at the base, immediately above the insertion point, \P j »», niidvein, «', principal and n", secondary lateral nerves, sU% marginal bast bundle, vbus, bundles of the upper, and vhls, of the lower surface of the leaf (cf. fig. 88!). G, Transverse section of a ligule immediately at the insertion point, ^^, ic, front-field, Iff, wing-field; the bundles of the wf turn their vessels to the stem-side, the bundles of the ic towards the leaf-side (cf. fig. 881). Fig. 88. P. repens Haoste. Longitudinal section through a node, schematized; explana- tion see above! «, stem, h, leaf, it\ ligule, front-field, ivf, wing-field, cc, central cylinder, vbic, vase, bundles of the ligule, vbtis, those of the upper, and vhls, of the lower surface of the leaf, mh, midvein of the leaf, vhw, bundles of the wing-field of the ligule, str, subepidermal bast strands of the stem. the cortex into the central cylinder, and the same is also true concerning the leaf. Not only the midvein and the lateral veins enter the central cylinder but also the bundles of the lower surface [vbls in the fig. 88). The bundles of the upper surface of the leaf and those of the intercarinal part of the ligule, again, descend into the lacunar system of the cortex but disappear immediately below the insertion point, and the internodal part of the stem accordingly is always devoid of interlacunar bast and vascular bundles. The bundles of the upper and lower surface of the leaf belong only to the basal fourth part of the leaf and the cross-section at th
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1910, bookyear1916
