CHAPTER IX. 



THE STEMS OF PLANTS. 



The various Growth of Trees. Internal Structure of Plant-stems. Wood and 

 Fibrous Cells. The Shafts of Palms. Climbing-plants. Their various Modes 

 of Attachment. Tree Buttresses. Defences of Plants. Thorns. Prickles. 

 Harmonies between the Trunks of Trees and the Wants of Man. The Voices of 

 the Forest. 



How different the growth and stature of our forest-trees ! Here 

 the fir symmetrically raises its stately pyramid to the skies; 

 there the oak widely extends its sturdy branches, like arms, 

 ready to give battle to the storm. The beech, the elm, the 

 poplar, the willow, the birch, have each their own well-defined 

 individuality, and enhance the beauty of the landscape by their 

 picturesque contrasts. The same pleasing variety strikes us in 

 plants of humbler pretensions. This shrub has but a few vertical 

 shoots, while its neighbour branches out in all directions ; here 

 growth tends ambitiously upwards ; there it humbly creeps 

 along the ground ; here it confronts you with a military stiff- 

 ness, as if determined rather to break than to yield ; there it 

 appears with a courtier-like pliability, ever ready to bend as the 

 wind blows. 



But, however different its growth may be, the trunk or stem 

 of a plant is in every case admirably proportioned to the. 

 weight it has to carry or to the resistance it has to encounter, 

 and in every case its texture has been made to harmonise with 

 its task. Thus, on examining the internal structure of our forest 

 trees, we find their woody fibres, which are long and pointed at 

 both ends like spindles, firmly wedged into each other, an ar- 

 rangement which of course gives the fabric of the trunk or 

 branches a greater power to resist the violence of the wind. 



Every year our forest trees add a new concentric layer or 

 ring to their circumference, so that the strength of their axis. 



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