. The elements of structural . ises—of the paroiclti/ma and theprosenclnjma. 169. Let us begin with the stem of a 167 shows a eection of a young shoot. The wholeof the white part is cellular tissue,the central portion being the dark wedge-shaped portionsare fibro-vascular bundles, consist-ing mainly of woody tissue, a fewvessels, easily recognised by theirlarger openings, being the shoot becomes older, thesebundles enlarge, and others are formed between them,so that the radiating channels of cellular tissue whichseparate them are in the eud r
. The elements of structural . ises—of the paroiclti/ma and theprosenclnjma. 169. Let us begin with the stem of a 167 shows a eection of a young shoot. The wholeof the white part is cellular tissue,the central portion being the dark wedge-shaped portionsare fibro-vascular bundles, consist-ing mainly of woody tissue, a fewvessels, easily recognised by theirlarger openings, being the shoot becomes older, thesebundles enlarge, and others are formed between them,so that the radiating channels of cellular tissue whichseparate them are in the eud re-duced to much smaller compafsthan in the earlier stages of growth(Tig. 168). The narrow channelsare the medullarij rai/s. Thecells of which they are composedare flattened by , a ring of wood isformed, the medulhiry rays intersecting it in fine lines,a-s the sawed end of almost any log will show. Outsidethe zone of wood is tlie hark, wliich at first consistsaltogetlier of cellular tissue. As the season advances,. Fig. 167.
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1879
