Text-book of structural and physiological botany . Fig. 128.—Vexil- Fig. 129.—Alternate lary aestivation aestivation of tulip,of Papiliona-cese. Fig. 130.—Quincun-cial aestivation. Fig. 131.—Contortedaestivation. By vernation is meant the position occupied by the se-parate leaves in the bud. This v^flat in the leaves of Coni-fers ; Am^Xy folded (^\g. 132) in those of the cherry and lime ;plicate or with many folds in those of the beech and birchFig. 133). In their length from the apex to the base leaves. Fig. 132. — Fig. 133. — Fig. 134.—Con-Simply fold- Plicate ver- volute verna-ed verna- nat
Text-book of structural and physiological botany . Fig. 128.—Vexil- Fig. 129.—Alternate lary aestivation aestivation of tulip,of Papiliona-cese. Fig. 130.—Quincun-cial aestivation. Fig. 131.—Contortedaestivation. By vernation is meant the position occupied by the se-parate leaves in the bud. This v^flat in the leaves of Coni-fers ; Am^Xy folded (^\g. 132) in those of the cherry and lime ;plicate or with many folds in those of the beech and birchFig. 133). In their length from the apex to the base leaves. Fig. 132. — Fig. 133. — Fig. 134.—Con-Simply fold- Plicate ver- volute verna-ed verna- nation. Fig. 136.—Involutevernation. Fig. 137.—Contortedvernation. are circinate, like the fronds of ferns, where the apex isrolled up towards the base ; convolute (Fig. 134), where onemargin is rolled up towards the mid-rib, as in grasses andbananas. The sepals of Fumaria are revolnte, the marginsbeing rolled outwards (Fig. 135); those of the sweet violet 86 Structural and Physiological Botany, on the contrary are involute (Fig. 136), or rolled inwardstowards the mid-rib. The petals of Convolvulus (Fig. 137)are contorted^^^vcdXiy ; those of the poppy irregularly <r;7/;;///<f^.With respect to their anatomical structure, it may be re-marked that buds are especially distinguished by the pre-sence of formative tissues. THE LEAVES. It will be seen from what has now been said that theLeaves are appendicular organs of the stem. The apex isalways formed first, and is therefore th
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