. The elements of botany for beginners and for schools. Botany. uo VEGETABLE LIFE AND WORK. [SECTION 16, layer of wood outside the preceding one, between that and the bark. This is exogenous growtii, or outside-growing, as the name denotes. 430. Some new bark is formed every year, as well as new wood, the former inside, as the latter is outside of that of the year preceding. The ring or zone of tender forming tissue between the bark and the wood has been called the Cambium Layer. Cambium is an old name of tlie physiologists for nutritive juice. And this thin layer is so gorged with rich nutrit
. The elements of botany for beginners and for schools. Botany. uo VEGETABLE LIFE AND WORK. [SECTION 16, layer of wood outside the preceding one, between that and the bark. This is exogenous growtii, or outside-growing, as the name denotes. 430. Some new bark is formed every year, as well as new wood, the former inside, as the latter is outside of that of the year preceding. The ring or zone of tender forming tissue between the bark and the wood has been called the Cambium Layer. Cambium is an old name of tlie physiologists for nutritive juice. And this thin layer is so gorged with rich nutritive sap when spring growtli is re- newed, tliat tbe bark then seems to be loose from the wood and a layer of viscid sap (or cambium') to be poured out between tlie two. But there is all the while a connection of the bark and the wood by delicate cells, rapidly mul- »f tiplying and growing. 431. The Bark of a year-old stem consists of beginning next the wood, — Tliis contains some. 480 three parts, more or loss distinct, namely, 1. TuE Liber or Fibrous Bark, the Inner Bark wood-cells, or their equivalent, commonly in the form of bast or bast-cells (411, Fig. 444), such as those of Basswood or Linden, and among herbs those of flax and hemp, wliich are spun and woven or made into cordage. It also contains cells which are named 5?>»(?-cells, on account of numerous slits and pores in their walls, by which the protoplasm of contiguous cells communicates. In woody stems, whenever a new layer of wood is formed, some new Uber or inner bark is also formed outside of it. Fig. 478. Piece of a stem of Soft Maple, of a year old, cut crosswise and length- wise. Fig. 479. A portion of the same, magnified. Fig. 480. A small piece of the same, taken from one side, reaching from the bark to the pith, and highly magnified: a, a small hit of tlie pith; h, spiral ducts of what is called the viedullary sJwath ; c, the wood; d, d, dotted ducts in the wood; €,e, annular ducts;/, the liber or i
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Keywords: ., bookpublishernewyorkamericanboo, booksubjectbotany, bookyear1887
