204 STATE HORTICULTURAL SOCIETY. 



In the pistil, the most important and ever-present part is the ovary 

 or ovule sac. The upper part of the ovary is elongated into the style, 

 some portion of which is modified into a secreting surface called the 

 stigma, or when the style is wanting, some portion of the ovary proper 

 is so modified for the same purpose. It is, however, in the ovary . 

 that our interest first centers. Here we find the ovules, which are to 

 ■serve as centers, from which after fertilization the seed or seeds are to 

 be developed. On the walls of this ovary, which has before been 

 fipoken of as the basal portion of the pistil, are developed minute cel- 

 lular structures called ovules. 



Various theories have been advanced as to the nature of this ovule. 

 Formerly it was considered to be homologous with the leaf-bud; at 

 present the accepted belief among the best scientists is that it is the 

 lobe of the leaf peculiarly developed, or an outgrowth of the leaf 

 either from its surfaces or edges. This ovule first appears as a single 

 TOW of cells, or a cluster of several rows, forming the nucleus of the 

 ovule, or as it is technically called, the nucellus. 



On the outside of the nucellus is soon developed a double coat 

 that almost envelops it. I say almost, for at one end there is a small 

 orifice called the foremen, the purpose of which we will notice later 

 on. Immediately below the foramen, within the integuments, a single 

 ■cell begins to elongate toward the other extremity of the ovule, which 

 after a series of segmentations becomes the embryo sac. We have 

 now reached the vital portion of the ovule. This embryonal sac is 

 filled with protoplasm in which is the true cell nucleus. This cell 

 nucleus by a series of divisions and arrangements of the emerging 

 parts, forms the antipodal cells at the base of the embryo sac, the cen- 

 tral secondary nucleus and the egg apparatus at the top immediately 

 below the foramen. We are now ready lor the act of fertilization, and 

 will for a moment consider the pollen grain. 



Of the pollen we will simply say that it is the granular, unicellu- 

 lar product of the anther of the stamens, protoplasmic in nature and 

 I)ossessed of nuclei. 



When the time of maturity comes to the flower, the secreting sur- 

 face of the stigma becomes covered with a tenacious substance, the 

 anther discharges its pollen, which in a variety of ways reaches the 

 stigmatic surface of the pistil. Almost immediately after coming into 

 contact with the moist surface of the stigma, the pollen grain swells, 

 and from its under surface projects one or more tubes that, passing 

 through the loose style substance, enters the ovule at the foramen and 

 ■comes into contact with the egg apparatus of the embryo sac. 



Immediately a marked change takes place in the appearance of the 



