ORGANS OF REPRODUCTION. 109 



two cells of the anther has two small lids or valves, 

 which open into the interior. 



The cells of the anthers are filled with a peculiar 

 matter termed pollen, which to the naked eye appears 

 like a sort of dust or flour, most frequently yellow, 

 but sometimes white, violet, or brown; and, when 

 viewed by the microscope, having various forms in 

 various species. 



M. Guillemin describes the grains of pollen as minute 

 bladders, containing granules l of extreme minuteness. 

 The bladders, may either be smooth and dry, as in the 

 pea, the potato, gentian, spurge, pinks and grasses; 

 or covered with small knobs, giving out a clammy 

 fluid, as in mallow, gourd, sun-flower, chicory, and 

 bindweed. When dry grains are exposed to water, 

 they change from spherical to elliptical; the viscid 

 grains burst, and scatter a liquid denser than water, 

 having myriads of granules swimming about in it 

 with circulatory motion. Amici has seen these in 

 motion for four hours. 



M. Adolphe Brongniart, on examining an anther in a 

 flower-bud long before blowing, found it in form of a 

 tissue of cells, each cell in the progress of growth be- 

 coming separated from the others, and forming one 

 grain of pollen, but sometimes these are enclosed in 

 other larger cells which progressively burst. Each 

 grain has an outer envelope, thickish, furnished with 

 pores, and sometimes with elevated points; and an 

 inner very thin, transparent, and unconnected with 



(1) In Latin, Fovilla. 



