142 



VIEWS OF THE MICROSCOPIC WORLD. 



Fig. 241. 



low ; but it is frequently found to be of a pui-ple, 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 rouo-h, 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 



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. 



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, 

 and the diameter of the small central cell, is less than the 

 three thousandth part of an inch. 



