264 HOW CROPS GROW. 



time with foliage. In this way, too, the gardener molds a 

 straggling, ill-shaped shrub or plant into almost any form 

 he chooses ; for by removing branches and buds where 

 they have grown in undue proportion, he not only checks 

 excess, but also calls forth development in the parts before 

 suppressed. 



Adventitious or irregular Buds are produced from the 

 stems as well as older roots of many plants, when they are 

 mechanically injured during the growing season. The 

 soft or red maple and the chestnut, when cut down, habitu- 

 ally throw out buds and new stems from the stump, and 

 the basket-willow is annually polled, or pollarded, to induce 

 the growth of slender shoots from an old trunk. 



Elongation Of Stems. While roots extend chiefly at 

 their extremities, we find the stem elongates equally, or 

 nearly so, in all its contiguous parts, as is manifest from 

 what has already been stated in illustration of its devel- 

 opment from the bud. 



Besides the upright stem, there are a variety of prostrate 

 and in part subterranean stems, which may be briefly no- 

 ticed. 



Runners and Layers are stems that are sent out hori- 

 zontally just above the soil, and coming in contact with the 

 earth, take root, forming new plants, which may thence- 

 forward grow independently. The gardener takes advan- 

 tage of these stems to propagate certain plants. The 

 strawberry furnishes the most familiar example of runners, 

 while many of the young shoots of the currant fall to the 

 ground and become layers. The runner is a somewhat 

 peculiar stem. It issues horizontally, and usually bears 

 but few or no leaves. The layer does not differ from an 

 ordinary stem, except by the circumstance, often accident- 

 al, of becoming prostrate. Many plants which usually 

 send out no layers, .are nevertheless artificially layered by 

 bending their stems or branches to the ground, or by at- 



