152 MEDICINAL HERBS AND POISONOUS PLANTS 



CHAPTER X 



TREES AND SHllUBS 



In this chapter Ave have grouped togetlier the trees 

 and large shrubs of medicinal value or o£ a poisonous 

 nature. It must be emphasized that the plants therein 

 contained have no necessary relationship, and have been 



)ed tofifether as a matter of convenience: the diflEi- 



grou 



culty in identifying a plant is lessened considerably if it 

 is known to be either a tree or a shrub. All the main 

 groups are represented, with the exception of the Mono- 

 cotyledons. In addition to the groups discussed above, a 

 few of the trees and shrubs of medicinal importance or of 

 a poisonous nature belong to the Gymnosperms, the lowest 

 group of Flowering Plants, and one which includes the 

 Pines, Larches, Cedars, &c. All the Gymnosperms are 

 trees and shrubs, and for our purpose we can pick out 

 any particular one more easily by directing our attention 

 to points of structure peculiar to it, rather than by draw- 

 ing up tables such as have served our purpose usefully 

 in regard to the Monocotyledons and Dicotyledons. 



The Oak {Qnercw^ Rohur), — The bark of young trees 

 (up to about twenty years old) is used medicinally as an 

 astringent, on account of the large amount of tannin 

 whicli it contains. Longitudinal incisions are made in 

 spring through the bark so that it can be removed in 

 strips. These, after being dried, are ready for the market. 

 On the Continent, in some districts, cattle which have 

 been kept indoors throughout the winter are liberated 

 hi the spring, at the time as it happens when the young 

 leaves of the Oak have not yet developed the tannin 

 whicli later appears in them. The cattle br-owse greedily 

 on the young leaves, a proceeding which later results in 



