. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 140 BARK strips of cambium giving rise to the lenticels subsequently become continuous with the corl^-caml^ium (Fig. 68). \Miere the corlc is deep-seated, the tissues external to it are practically cut off from all sources of food and all connection with the interior, and therefore die away. These dead tissues, on the outside of the cork, are shed sooner or later, leaving the latter exposed as hark. In some plants [ Beech, Oak) the same cork-cambium continues to divide year after year, although inactive d
. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 140 BARK strips of cambium giving rise to the lenticels subsequently become continuous with the corl^-caml^ium (Fig. 68). \Miere the corlc is deep-seated, the tissues external to it are practically cut off from all sources of food and all connection with the interior, and therefore die away. These dead tissues, on the outside of the cork, are shed sooner or later, leaving the latter exposed as hark. In some plants [ Beech, Oak) the same cork-cambium continues to divide year after year, although inactive during the winter, so that a thick mass of cork is formed. This is also the case in the Cork Oak [Qnercus sttber), which is the main source of the commercial article. The first cork, which. c,c- Fig. 68.—Transverse section through a lenticel (/.) of the Elder {Sambucus). , cork-cambium ; ni, mechanical tissue. here arises subepidermally, is, howe\'(T, of no value, being re- moved \\-lien the tree is ten to fifteen years old, the cortex thus exposed forming a new phellogen which gives rise to the thin-walled cork of commerce. This is peeled off every eight to twelve years. In most woody plants the first-formed phellogen ceases to di^•ide, and indeed itself becomes changed into a la\'er of cork, at a comparatively early stage. A new cambiimi their arises at a deeper level in the cortex, produces a fresh zone of cork, and then in its turn passes out of action, to be succeeded b^' another situated still deeper. The bark formed in this \\'ay consists of alternating layers of cork and dead cortex, and comprises all the tissues beyond the most recently established phellogen. When. 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 Fritsch, Felix Eugene, 1879-; Salisbury, E. J. (Edward James), Sir, b. 1886. Londo
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpl, booksubjectplants
