. Botany for high schools and colleges. Botany. 156 generally loosely arranged, with large intercellular spaces be- tween them (Figs. 131 and 133), and these are in free com- munication with the external air by means of the stomata. It most frequently happens that this loose tissue is in the under part of the leaf, while the upper portion is composed of one or more layers of closely placed cells ; and this agrees with the general distribution of the stomata, there being usually many more on the under than the upjjer surface. 203.—The upper denser tissue, termed palisade tissue, is com
. Botany for high schools and colleges. Botany. 156 generally loosely arranged, with large intercellular spaces be- tween them (Figs. 131 and 133), and these are in free com- munication with the external air by means of the stomata. It most frequently happens that this loose tissue is in the under part of the leaf, while the upper portion is composed of one or more layers of closely placed cells ; and this agrees with the general distribution of the stomata, there being usually many more on the under than the upjjer surface. 203.—The upper denser tissue, termed palisade tissue, is composed of elongated cells, which stand at right angles to the surface of the Pig. 13Q.—Section of the" pali- , » /t^- ioi\t x- sade" tissue of the leaf of Xchi- leal (lig. 131). in cross-section the ?h7a's1Sie'"'^rfeC'oi''tJ? palisade-cells are cylindrical, with rhioropryiis.'amSe1:'^xm- Small intercellular spaces between t^em (Fig. 132), or in some cases they are more or less compressed and angular. In general, palisade tissue is confined to the upper surface of the leaf, the lower being occu- pied by the loose tissue previously naentioned ; but there are some cu- rious exceptions to this rule. The most notable of these is found in the leaf of Silpliium laciniatum— the so-called Compass Plant*—of the Mississippi Valley; its chloro- phyll-bearing parenchyma is almost entirely arranged as palisade tissue, so that the upper and lower por- ^lllici^lT^^"^ ^^k/Zt tions are almost exactly identical f^^i" ^o*/'"- "^k^" parallel to tiie ,_,. ,„,.•' mi leaf Furface. Several of the cells m structure (b Ig. 134). The Ver- a™ drawn showing their chloro- tical leaves of the Manzanita of drawing by j. c. Arthur! the Pacific Coast {Ardostaphylos pungens, var. platyphylla) have a similar Please note that these images are extracted from scanned page images that may have been digitally enhanced for re
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1888
