TREES— SHRUBS— R 007 S. 



than 20 feet in height may be called a tree, and shrubs are really small, spreading 

 trees, less than 20 feet high, and they form branched stems rather than solitary stems, 

 or trunks, or boles. 



Trees and shrubs are t'cergreen if they retain their leaves green throughout the 

 winter, and deciduous if they shed them on the approach of frost. They ma}^ be of 

 all forms or shapes, such as pyramidal, as in conifers ; columnar, as in Lombardy 

 poplar, cypress, and others ; spreading, as in oak and sycamore ; weej)ing, as in some 

 varieties of birch, elm, willow, etc, Pollarded trees are those whose trunks or boles 

 are periodically topped or thinned, or denuded of 

 branches. 



EooTS. 



These are the first growths produced by the germi- 

 nating seed, and their functions are at least threefold 

 in character. Their primary object is to serve as food- 

 seekers and absorbers of water from the earth, holding 

 as it does various soluble food salts in solution. Though 

 roots absorb soluble nitrates, they are really drinking 

 organs, most of the solid matter (95 per cent. ) found in 

 adult plants having really been absorbed from the air by 

 their leaves. 



Eoots also act as grapplers, or anchors, by which 

 most plants, and even large trees, are held firmly in 

 the ground in an erect position. In rocky places it 

 is often wonderful to see the beautiful adaptability of 

 tree and shrub roots, as they clasp and ramify over 



two seed leaves or cotyledons. 



huge stones, and take firm grip in the smallest of 



crevices. The curious manner in which plants grow from seeds on old walls, ruins and 

 towers, afford striking proof of root adaptability. 



The growing points, or root-tips, are the most plastic and active, as they stitch or 

 wriggle through the soil, and these growing points are highly sensitive to their sur- 

 roundings. So much so, that Darwin has pointed out that if it should ever be possible 

 to discover anything in plant life analogous to a brain, it would be found to exist in 

 these root-tips, that, under some conditions, actually seem to think and reason as well 

 as feel. 



Fig. 7. Seedling Plant. 

 Showing radicle with root-hairs and 



