FIRST LESSONS IN FRUIT GROWING-II. 



THE STEM. 



>HE stem is that part of the plant 

 which grows upward from the col- 

 lar, bearing the leaves or branches. 

 In some plants it is so short as not 

 to be apparent, as for example, the straw- 

 berry. The length and nature of the stem 

 determines very largely the character of the 

 plant. Woody plants having apparently no 

 stem, but which have the branches springing 

 from the collar, like the currant and lilac, 

 are called bushes or shrubs. Plants having 

 a stem which twines or climbs for support, 

 like the grape, or hop, are called vines. 

 A plant worthy of the name of tree has a 

 well-derined stem which supports the 

 branches. When it is bare of branches for 

 some distance from the ground, it is com- 

 monly known as the trunk. 



STRUCTURE OF A STEM. 



The study of a cross-section of the trunk 

 of any of our forest or fruit trees reveals an 

 interesting structure. In the centre will be 

 seen the pith, next to this the heart wood 

 and sapwood, and on the outside the inner 

 and outer bark. But let us look into these 

 more closely. 



The Pith. — The pith is a soft, spongy 

 substance found in the centre of both stem 

 and branches. In soft wooded species, like 

 the elder or grape, it is comparatively large, 

 while in hard wooded species, such as the 

 apple and pear, it is quite small. In young 

 shoots, it is soft and succulent, holding 

 moisture like a sponge, but in the older 

 parts of the tree it becomes dry and shriv- 

 elled, or may rot away altogether. Its use 

 apparently, then, is to act as a reservoir to 

 hold moisture in the young and growing 

 parts of the tree. 



The Wood. — The wood, which makes 

 up the greater part of the trunk, is of two 

 kinds. That on the inside is heart wood. 

 This is the older wood, which has become 

 firm and mature by age. It is generally of 

 a darker color than the sapwood surround- 

 ing it. In the walnut, it becomes a very 

 dark, rich color, and constitutes the most 

 valuable part of the tree. 



The line of demarkation between the heart 

 wood and sapwodd is often quite distinct, 

 but the annual increase in the heart wood 

 comes from the gradual maturing and dry- 

 ing of the inner layers of sapwood. 



