FRUCTIFICATION OF PLANTS. 255 



on the winds to considerable distances. It is sometimes 

 seen covering the shores of lakes after heavy showers which 

 wash it down from the air, and has been thought to be sul- 

 phur produced by the lightning, by persons not acquainted 

 with its character and origin. A field of evergreen sweet 

 corn grown by the author, half a mile from any other corn 

 field, and with a large piece of woods intervening, w T as so 

 much fertilized by the pollen from this distant field as to 

 have been spoiled for seed. 



The pollen of various plants differ so much in appearance 

 when examined under a microscope as to be easily recog- 

 nized as belonging to its special plant. The minute grains 

 of it are thus exceedingly interesting objects for microscop- 

 ical study. These grains of pollen vary in shape; some are 

 round; some oval; some angular and many sided; some 

 triangular; others double; treble; and in other ways are 

 exceedingly diversified. They are made up of two coats, 

 the inner one being filled with a fluid of a thickish con- 

 sistence, in which are mixed a great number of minute grains. 



THE PISTIL is made up of an ovary, a style, and a stigma. 

 The ovary and the stigma are the most essential parts; the 

 style being the stalk which holds up the stigma, and the 

 connecting channel between the two. The ovary is the re- 

 ceptacle for the ovules or embryo seeds, which adhere to the 

 inner sides of the cell or cells, as may be seen in the pea; 

 the ovary or pod of which contains the seeds arranged along 

 its length and attached to the side of it. The ovules, con- 

 sist of a mass of pulpy tissue called the nucleus and are 

 covered by one or tw r o coats. 



The embryo is formed in the nucleus, and the coats be- 

 come the coverings or skin of the seed. There is an open- 

 ing through the coats of the ovary near where the apex of 

 the ovules is situated, and an orifice in the ovule which 

 corresponds with it. 



FRUCTIFICATION, or the process of impregnating or vi- 

 talizing the seed, is the final function of the flower; and is 

 effected as follows. When the flower is ripe for the per- 

 formance of this function, the anther bursts and the pollen 



