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 pas.<iiig into petals. 



73. The stamens vary in the different kinds of plants, in re- 

 spect to their numher, position, relative length, connection, and 

 presence. Upon these five different conditions of tire stamens, 

 the TWENTY-FOUR ARTIFICIAL CLASSES of Liuuajus are founded. 



74. 1st. Numher. The first eleven classes are founded upon 

 the numher of the stamens — the stamens being ^%o free (63, 

 c), and of equal length. Their names arc derived from the 

 Greek numerals combined witli aK^os? (-57, note), as follows : — 



Class I, MoNANDRiA (ftovog, solitaiy,) includes all genera (52) 

 of plants with one stamen to each flower. 



