. A class-book of botany, designed for colleges, academies, and other seminaries ... Illustrated by a flora of the northern, middle, and western states; particularly of the United States north of the Capitol, lat. 38 3/4. , agreeably to the beautiful ITS NORMAL STRUCTURE. 31 theory of the transformation of the leaves into the floral organs, * to which allu-sion has ah-eady been made (§ 25). When the bud is developed into a branch,instead of a llower, the leaves are usually arranged in a simple spiral line. Thisspire may be broken up into equal circles or whorls, from causes to be hereafterexpl
. A class-book of botany, designed for colleges, academies, and other seminaries ... Illustrated by a flora of the northern, middle, and western states; particularly of the United States north of the Capitol, lat. 38 3/4. , agreeably to the beautiful ITS NORMAL STRUCTURE. 31 theory of the transformation of the leaves into the floral organs, * to which allu-sion has ah-eady been made (§ 25). When the bud is developed into a branch,instead of a llower, the leaves are usually arranged in a simple spiral line. Thisspire may be broken up into equal circles or whorls, from causes to be hereafterexplained. In cither case the leaves of one spire, or cinde, do not issue from tliestem at points exactly over the leaves of the next circle below, but over the inter-vals between them. 62. This simple nonnal structure of the flower is, however, subject to manyapparent exceptions, so tliat few, comparatively, are found perfectly conformal^leto it. Of these few the order Linacea affords good exaiiiples. In the flax(Linum) the flower is built upon the normal plan, consisting of 5 sepals, 5 petals,5 stamens, and 5 pistils (each with 5 double carpels), all alternating with eachother, according to the diagram (Fig. 5; 1).. FIG. 5. —Plan of flowers; 1, ora. regular and symmetrical flower, as ihe flax (Linum); 2,of the cherry, showing the four whorls of stamens ; 3, of the primrose, showing- the positionof the suppressed row of stamens; 4, of the Samolus, showing the position of the 5 abortivestamens; 5, of a labiate flower, as the hemp-nettle (Galeopsis), where one stamen and onecarpel is wanting; 6, of a cruciform flower, as mustard, where the stamens are in twowhorls, two of those in the outer whorl and two carpels being suppressed. 63. If, with this adopted standard, we compare the numerous * This theory was first suggested by Linnaeus, the founder of Systematic Botany, and sub-sequently by Wolff and Goethe. After having been long unheeded by botanists, it has atlength been revived
Size: 1900px × 1315px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, booksubjectbotany, bookyear1848
