9 



HOW PLANTS ARE FERTILISED. 



At first sight nothing would appear to be easier of accomplishment than 

 that the pollen in the stamens should be conveyed to the immediately adjacent 

 stigmas in order to fecundate them. And yet, strange as it may seem, the 

 the most elaborate and in some cases intricate contrivances are employed by 

 nature to avert this consummation. It is now a well known and widely re- 

 cognised fact, that in the animal world intermarrying or interbreeding is not 

 conducive to the well-being of the stock. Those communities or sects, in 

 which intermarriage is inculcated as a duty, are soon found to deteriorate in 

 physical stamina and mental prowess. The farmer also knows full well how 

 soon his flocks and herds degenerate unless his stock is renovated by the 

 infusion of fresh blood. And he is kept always up to the mark of the 

 higher level by the depreciation of prices, entailed by keeping breeds of an 

 inferior strain. The agriculturist has long practised rotation of crops in 

 order to take full advantage of the capabilities of his soil, and he, too, soon 

 learned the beneficial effects of a change of seed, i.e. the produce of similar 

 plants grown in different soil. The horticulturist and gardener attains the 

 same end by eliminating the weaker and more worthless amongst his seed- 

 lings, thus perpetuating only the finer and choicer varieties, which he assidu- 

 ously propagates by layers, grafts, budding, cuttings, &c, so as to retain the 

 good and expunge the noxious qualities of the plants. Nature by similar, 

 if perhaps slower, methods attains the same end. The survival of the fittest, 

 and the fierce struggle for existence, may be studied during each recurring 

 spring-time, in woodland, field, or roadside, where the innumerable seedlings 

 are pushing through the ground and elbowing each other out of the way, the 

 stronger and more vigorous obtaining and keeping possession of the limited 

 growing space. It is then that every little advantage, however slight, tells 

 in favour of the fortunate possessor, and the inheritor of the most robust 

 constitution is certain to be the winner in life's race. This being so, num- 

 erous experiments have tested and proved that seeds, the result of cross- 

 fertilisation, produce a stronger progeny, hardier and more prolific than others 

 the product of self-fertilised flowers. By self-fertilised is meant when the 

 pollen from the stamens is conveyed to the stigma of the same individual 

 blossom, as if, for example, the pollen of the numerous stamens of a rose or 

 buttercup were to be shed upon the central stigmas which they surround. 

 Whilst in cross-fertilisation the pollen of one flower has to be conveyed to 

 the stigmas of another blossom, it may be on the same plant, but for its full 

 efficacy to be obtained it should be transferred to a different plant. Of course 

 it must be of the same species, otherwise a hybrid would be the result, 



