. The botany of crop plants; a text and reference book. Botany, Economic. STEMS 27 the limits of two successive years' growth are marked by bud scale scars of terminal buds. In this way we may determine the age of a twig. Close observation of the twig will reveal a number of whitish spots on the bark. These are lenticels (Fig. 11), structures on the stem composed of a mass of loosely fitting cells which permit the diffusion of gases inward and outward. Except for the lenticels, the bark prevents the free passage of air, and also the loss of water from underlying stem '^e^om mt^^ Fig. I
. The botany of crop plants; a text and reference book. Botany, Economic. STEMS 27 the limits of two successive years' growth are marked by bud scale scars of terminal buds. In this way we may determine the age of a twig. Close observation of the twig will reveal a number of whitish spots on the bark. These are lenticels (Fig. 11), structures on the stem composed of a mass of loosely fitting cells which permit the diffusion of gases inward and outward. Except for the lenticels, the bark prevents the free passage of air, and also the loss of water from underlying stem '^e^om mt^^ Fig. II.—Section of the lenticel of elder. (After Sirasburger.) From A of Botany by Coulter, Barnes, and Cowles. Copyright, by the American Book Company, Publishers. How Does a Stem Grow in Length?—A bud is a young shoot. A lengthwise section of a leaf bud shows a cone- shaped growing point (young stem) upon which is a number of young leaves. These leaves come off at regular intervals, following identically the same arrangement as they do in the adult twig. The growing point, then, consists of a number of very much shortened internodes. Growth in length of the shoot consists in the elongation of these in-. 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 Robbins, Wilfred William, 1884-1952. Philadelphia, P. Blakiston's Son & Co
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectbotanyeconomic
