36 



THE FLOWER. 



usually spherical, but in 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 gi-ain of pollen has heen ascertained to consist of a membranous sack 

 containing a fluid. Li this fluid are suspended molecules of inconceivable 

 minuteness, possessed of a tremulous motion. TVlien the membrane is exposed 

 to moisture, it swells and bui'sts, discharging its contents. (Fig. 12.) 



71. Physiological structure. Tlie filament consists of a bundle 

 of deUcate ligneous tissue, \vith spiral vessels, smTounded by 

 cellular tissue, the same tissues wliich compose the stem of the 

 leaf (260). The same tissues have also been traced into the 

 connectile. The anther consists almost wholly of cellular tissue, 

 corresponding to the fleshy substance (parench^ana) of the leaf 

 The pollen consists of disintegrated bladders of the same tissue. 



72. Theoretical structure. Thus it is evident, as we have ah-eady seen, that 

 however much the stamen may differ in aspect from a leaf, they both have the 

 same original plan. This is further e-vadent, from the gi-adual transition of sta- 

 mens into petals, as seen in the water-lily or the double rose. In the fonner, the 

 process is so gradual that the outer whorls exactly resemble petals, except in having 

 the tops developed into yellow anthers, while in the rose we find organs in every 

 conceivable state of transition from stamens to petals. That the petals are modi- 

 fied leaves, will hereafter be more definitely shown (106). 



FIG. 8. — Stamens of the water-lily gradually passing into petals. 



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

 spect to their number, position, relative length, conyiection, and 

 presence. Upon these five different conditions of the stamens, 

 the TWENTY-FOUR ARTIFICIAL CLASSES of LimisBus are founded. 



74. 1st. Number. The fii'st eleven classes are founded upon 

 \he number of the stamens — the stamens being also /;-ee (63, 

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

 Greek numemls combined vnth. uidQeg (57, note), as follows : — 



Class I, MoNANDRiA (.Moj'oc, Solitary,) includes all genera (52) 

 of plants with one stamen to each flower. 



