. Comparative anatomy of the vegetative organs of the phanerogams and ferns;. Plant anatomy; Ferns. TRACHEA. ^57 of the leaves of many Mesembryanthema, e. g. M. stramineum. A less common form of the fibres, corresponding to the bordered pits, is that of which the section has the outline of a short-armed recumbent [—, while the fibre is attached to the thin wall by the free end of the single (here horizontal) arm. This is the case in the closely- wound spiral tubes, which show transitional forms to the reticulate, and, in many woody stems, are first fully formed when the extension of the intern
. Comparative anatomy of the vegetative organs of the phanerogams and ferns;. Plant anatomy; Ferns. TRACHEA. ^57 of the leaves of many Mesembryanthema, e. g. M. stramineum. A less common form of the fibres, corresponding to the bordered pits, is that of which the section has the outline of a short-armed recumbent [—, while the fibre is attached to the thin wall by the free end of the single (here horizontal) arm. This is the case in the closely- wound spiral tubes, which show transitional forms to the reticulate, and, in many woody stems, are first fully formed when the extension of the internode is ended, as is the case in Artanthe elongata, Nerium, Convolvulus Cneorum. The single arm is. FIG. s6».—Piece of an annular vessel from the stem of Zea Mais, h the thin wall, on which the limits of the adjoining cells are visible, r annular fibres, y one of these cut through, iy the strata of the same (350), From Sachs' Textbook. Fig. 57.—Saururus cernuus. Piece of a radial longitudinal section through a vascular bundle of the herbaceous stem; r in- most, narrow, distorted annular-vessel. To thejeft of this successively (i) spiral vessel, with loosely wound single fibre, which in two places runs back into itself, so as to form a ring; the thin wall between the spirals of the fibre has given way; (2) spiral vessel with very narrow flattened curve, cut longitudinally in half, with exception of the upper margin; (3) scalariform reticulate vessel; yselerenchyraa (or bast) fibres. The curves of the spiral fibres rise in the drawing in the opposite direction to the course they really pursue (375). in these cases almost always smaller than the two others; in the above-named Artanthe it is very inconspicuous compared with the other strongly-protruding parts. The Trachea with spiral fibrous thickening show considerable variety in the number of the fibres, and the steepness and direction of their coils. Their number is often only 1-2 in the narrow tubes, which are first forme
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Keywords: ., bookcentury1800, bookdecad, booksubjectplantanatomy, bookyear1884
