. Botany for high schools and colleges. Botany. ARBANOEMENT OF LEAVES. 153 as follows :* " Ifew lateral members tave their origin above the centre of the widest gaps which are left at the cir- cumference of the punctum vegetationis between the in- sertions of the nearest older members of the same kind;" and no doubt this is one of the most important immediate causes which determine where each new leaf is to arise. If it be asked why, then, are not all leaves arranged alike, the answer must be looked for in the differences in structure of the puncta vegetationes. In cases where there
. Botany for high schools and colleges. Botany. ARBANOEMENT OF LEAVES. 153 as follows :* " Ifew lateral members tave their origin above the centre of the widest gaps which are left at the cir- cumference of the punctum vegetationis between the in- sertions of the nearest older members of the same kind;" and no doubt this is one of the most important immediate causes which determine where each new leaf is to arise. If it be asked why, then, are not all leaves arranged alike, the answer must be looked for in the differences in structure of the puncta vegetationes. In cases where there is an apical cell, the arrangement of the leaves may be directly traced to its mode of division. In Phanerogams it is often clearly due. Fig. 130S.—CrosB-section of the leaf-bnd of the chestnut (Caataneavesea). «', v^, the scale-like leaves ;/i,/!',,/', etc., the nidimentary leaves; s^s', s's', ete., the stipules belonging to tlie correspondingly numbered leaves. Magnified. — After Hofmeister. to a difference in the size and form of the punctum vegeta- tionis ; in Conifers and Composites, for example, it is com- mon for a change in the arrangement to take place in pass- ing from the foliage leaves to the bracts of the inflorescence upon the same stem, the number of ranks in such cases being greater on the larger axes. Doubtless some of the dif- ferences can be explained only by taking into account, also, the inherited peculiarities of the plant. * "Allgem. Morpliol.," p. 482, and quoted in Sachs' "Te^t-Book," p. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bessey, Charles E. (Charles Edwin), 1845-1915. New York : H. Holt
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1885
