. A class-book of botany, designed for colleges, academies, and other seminaries where science is taught ... Illustrated by a flora of the northern United States particularly New England and New York. Botany; Plants -- United States; Plants -- Canada. 36 THE FLOWER. usually spherical, but iii some plants cubical, in others triangu- lar, in others still, polygonal, &c., always being of the same form in the same species. (Fig. 7.) a. Each grain of pollen has heen ascertained to consist of a membranous sack containing a fluid. In this fluid are suspended molecules of inconceivable minuteness,
. A class-book of botany, designed for colleges, academies, and other seminaries where science is taught ... Illustrated by a flora of the northern United States particularly New England and New York. Botany; Plants -- United States; Plants -- Canada. 36 THE FLOWER. usually spherical, but iii some plants cubical, in others triangu- lar, in others still, polygonal, &c., always being of the same form in the same species. (Fig. 7.) a. Each grain of pollen has heen ascertained to consist of a membranous sack containing a fluid. In this fluid are suspended molecules of inconceivable minuteness, possessed of a tremulous motion. When the membrane is exposed to moisture, it swells and bui'sts, discharging its contents. (Fig. 12.) 71. Physiological structure. The filament consists of a bundle of deUcate Ugneous tissue, with sphal vessels, surroimded by cellular tissue, the same tissues which compose the stem of the leaf (260). Tlie same tissues have also been traced uito the connectile. The anther consists almost wholly of cellular tissue, corresponding to the fleshy substance (parenchyma) of the leaf The pollen consists of disintegTated bladders of the same tissue. 72. Thcordkal structure. Thus it is e\'ideut, as we have aheady seen, that however much the stamen may dift'er in aspect from a leaf, tliey both have the same original plan. This is further evident, from the gradual transition of sta- mens into petals,, as seen in the water-hly or the double rose. In the fonner, the process is so gradual that the outer whorls exactly resemble petals, except in ha\'ing the tops developed into yellow anthers, while in the rose we find organs in every conceivable state of transition from stamens to petaj?. That the petals are modi- fied leaves, will hereafter be more definitely shown (106).. FIG. 8. — Stamens of the water-lily gradually ;iiig into petals. 73. The stamens vary in the different kinds of plants, in re- spect to their numher, position, relative length, conn
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