144 



VIEWS OF THE MICROSCOPIC WORLD. 



low ; but it is frequently found to be of a purple, white, blue, and brown hue ; 

 and in some flowers it appears in the form of clear, transparent grains. The sur- 

 face of the particles in some instances is smooth, and in others rough, and in 

 many cases it is studded with delicate spines or thorns. The pollen is contained 

 in a receptacle termed the anther, which at the proper time opens and liberates 

 the imprisoned particles. These are not unfrequently borne upon the atmosphere 

 to a great distance ; for trees have been known to be fructified by pollen, which 

 must have been wafted through the space of three miles. The number of par- 

 ticles contained in each anther, varies from a few hundreds to several thousands. 

 When the grains of pollen are viewed with a microscope, at the time they are 

 fully matured, they are seen to separate, and an oily liquid flows from the in- 

 terior. A similar result occurs if a grain of pollen is thrown upon the surface 

 of water. It there gradually swells and at last bursts, when a liquid escapes from 

 the atom, which spreads in a thin film over the surface of the water in the same 

 manner as a drop of oil. This liquid has been regarded as the fructifying matter 

 of the plant. An anther of the mallow is delineated in figure 241, and the 

 Fi ^ grains of pollen that it bears are indicated by the 



round spots in the middle of the drawing. Figure 

 242, shows the atoms of pollen more highly mag- 

 nified. m 



The pollen of the morning-glory 

 is delineated in figure 243. It ap- 

 pears under the microscope of a 

 spherical form, like a small pea, 

 with the surface thickly set with 

 minute spines. It is of a pearly 

 white color, and appears to be com- 

 posed of an assemblage of small cells, the parti- 

 tions of which are indicated by the light which passes 

 through them, on account of their transparency ; 



and in the figure their situation and mode of arrangement are distinctly marked 

 by the lighter parts of the drawing. The real diameter of these particles of pol- 

 len is the one hundred and twenty-fifth part of an inch. 



INDIAN CORN. The pollen of the Indian corn is exhibited in figure 244. In 

 Fig. 244. shape, the grains resemble those of buckwheat ; the central 

 parts are thin and transparent, and are probably cells filled 

 with fluid. The length of a side of one of these atoms does not 

 exceed the eight hundredth and thirtieth part of an inch, 

 & ^ G ^ and the diameter of the small central cell, is less than the 

 three thousandth part of an inch. 



