. Wood; a manual of the natural history and industrial applications of the timbers of commerce. Wood; Timber. PITH OF BROAD-LEAVED TREES 25 In the last-mentioned case the projections of the primary xylem into the pith may give the pith a wavy or crenate outer margin, as in Hawthorn, Rowan, Laburnum, Horse-Chestnut, or Elder ; or this margin may appear even, as in Elm, Hazel, and Dogwood (Cornus). In the Walnuts the pith has an interrupted or chambered structure : in the Elder it soon dies and disintegrates, leaving the stem hollow; whilst in young stems of Elm the inner portion of it. -\ /; Fi
. Wood; a manual of the natural history and industrial applications of the timbers of commerce. Wood; Timber. PITH OF BROAD-LEAVED TREES 25 In the last-mentioned case the projections of the primary xylem into the pith may give the pith a wavy or crenate outer margin, as in Hawthorn, Rowan, Laburnum, Horse-Chestnut, or Elder ; or this margin may appear even, as in Elm, Hazel, and Dogwood (Cornus). In the Walnuts the pith has an interrupted or chambered structure : in the Elder it soon dies and disintegrates, leaving the stem hollow; whilst in young stems of Elm the inner portion of it. -\ /; Fig. 21.—Tangential longitudinal section of Oak, magnified 50 diameters, showing transverse sections of pith-rays. (After Mtiller, from The Oak, by permission of Prof. Marshall Ward and Messrs. Kegan Paul, Trench, Triibner & Co.) \ has thin walls and loses its protoplasm, whilst the outer part becomes thick-walled but retains its cell-contents. ^ The pith-rays of broad-leaved trees are in general far more conspicuous than those of conifers. In Oak the large primary pith-rays extending from pith to cortex are often twenty or more cells jn width, appearing as long, clearly defined, greyish hues in a transverse section of the stem (Fig. 19). The secondary pith- rays are much narrower as well as shorter (Fig. 20). In a tan-. 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 Boulger, George Simonds, 1853-1922. London, E. Arnold
Size: 1185px × 2110px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjecttimb, booksubjectwood
