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The principles of biology . homologous parts of the same tree: a being the leadingshoot; I a lateral- branch near the top, and c a lateralbranch lower down. There is here a double exemplifica-tion. While the branch a, as a whole, has its branchlets 132 MORPHOLOGICAL DEVELOPMENT. arranged with tolerable regularity all round, ia corre-spondence witL. its equal exposure on all sides, each, branch-let shows by its curve as much bilateral symmetry asits simple form permits. The branch b, dissimilailycircumstanced on the side next the main stem and onthe side away from it, has an approximate bilater
The principles of biology . homologous parts of the same tree: a being the leadingshoot; I a lateral- branch near the top, and c a lateralbranch lower down. There is here a double exemplifica-tion. While the branch a, as a whole, has its branchlets 132 MORPHOLOGICAL DEVELOPMENT. arranged with tolerable regularity all round, ia corre-spondence witL. its equal exposure on all sides, each, branch-let shows by its curve as much bilateral symmetry asits simple form permits. The branch b, dissimilailycircumstanced on the side next the main stem and onthe side away from it, has an approximate bilateralnessas a whole, while the bilateralness of its branchlets varieswith their respective positions. And in the branch c, havingits parts stUl more differently conditioned, these traits ofstructure are still more marked. Extremely strong contrastsof this kind occur ia trees having very regular modes ofgrowth. The uppermost branches of a Spruce-fir have radiallyarranged branchlets: each of them, if growing vigorously,repeats t
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectbiology, bookyear1864