112 THE AMERICAN BOTANIST. 



increases in size until, finally, with the contained embryo, 

 and occasionalh' with some reserve food material in addi- 

 tion, it forms what is called a ripe seed. It might be 

 thought that, since in most flowering plants the stamens 

 are so closely related in position to the carpels, it would 

 be a relatively easy matter for pollen to fall on the stigma 

 and fertilize the ovules of its own flower. But this rarely 

 happens, although barley and some of the grasses furnish 

 examples where such a thing does take place, for it is 

 known that they are persistently self-pollinated without 

 the species seeming to suffer deterioration from this in- 

 and-in breeding. Here it is that Nature plays into the 

 hands of the producer of new breeds, w^ho has been able 

 to change a two-rowed into a six-rowed barley, with all 

 the characters of a first-class malting variety. An infinite 

 number of new and distinct breeds of oats, barley, wheat, 

 clovers, grasses and roots have been produced by dexter- 

 ous manipulation of the flowers before they had pollinated 

 themselves. In some flowers this self-fertilization has been 

 prevented by mechanical means, the respective lengths or 

 positions of the involved organs being unsuitable. In the 

 case of unisexual flowers, that is, those containing only 

 stamens or carpels, respectively, self-fertilization can never 

 take place, and it is in such cases that insects play an im- 

 portant part in Nature. It may happen that the stamens 

 and carpels do not ri])en at the same time. This is, how- 

 ever, a subject by itself, and we shall continue it in a sub- 

 sequent issue. — Indian Planting and Gardening. 



LEAVES. 



To the popular mind the aspect of a full foliaged tree 

 suggests the idea that it is the function of the ramifying 

 fabric of trunk, branches and twigs to produce the leaves 

 which bedeck them ; whereas in point of tact, it is the 

 latter which are the builders both for themselves and the 

 woody portions which bear them, plus the unseen laby- 

 rinth of far spreading roots which lie beneath the soil, and 

 often rival in extent the aerial branches above it. 



