23 FRCIT-GARDENXSTG. 



anotlier part of this work, I shall direct the reader's attention 

 to the operation of Cross-Fertilization. 



This is effected by the action of the pollen of one plant 

 upon the stigma of another. The nature of this action ia 

 highly curious. Pollen consists of extremely minute hollow 

 balls or bodies ; their cavity is filled with fluid, in which swim 

 particles of a figure varying from spherical to oblong, and hav- 

 ing an apparently spontaneous motion. The stigma is com- 

 posed of very lax tissue, the intercellular passages of which 

 have a greater diameter than the moving particles of the 

 pollen. When a grain of pollen comes in contact with the 

 stigma, it bursts, and discharges its contents among the lax 

 tissues upon which it has fallen. The moving particles de- 

 scend through the tissues of the style, until one, or sometimes 

 more, of them find their way, by routes especially destined by 

 nature for this service, into a little opening in the integuments 

 of the ovulum or young seed. Once deposited there, the par- 

 ticle swells, increases gradually in size, separates into radicle 

 and cotyledons, and finally becomes the embryo, — the part 

 which is to give birth, when the seed is sown, to a new indi- 

 vidual. Such being the mode in which the pollen influences 

 the stigma, and subsequently the seed, a practical consequence 

 of great importance necessarily follows, viz. that in all cases 

 of cross-fertilization, the new variety will take chiefly after its 

 poUiniferous or male parent ; and that at the same time it will 

 acquire some of the constitutional peculiarities of its mother. 

 Thus the male parent of the Downton Strawberry was the Old 

 Black, the female a kind of Scarlet. In Coe's Golden Drop 

 Plum, the father was the Yellow Magnum Bonum, the mother 

 the Green Gage ; and in the Elton Cherry, the White Heart 

 was the male parent, and the Graffion the female. 



The limits within which experiments of this kind must be 

 ijonflned are, however, narrow. It seems that cross fertiliza- 

 tion will not take place at all, or very rarely, between different 

 species, unless these species are nearly related to each other : 

 and that the offspring of two distinct species is itself sterile, or 



