152 BRITISH PLANTS 



laurel, hemlock, woody nightshade, foxglove, rhubarb, 

 spurge-laurel, chamomile, gentian, valerian, dandelion, 

 nettle, etc. 



Economic Botany is the study of plants from the point 

 of view of their utility to man. We have already dealt 

 with the most important side of the subject — human food. 

 But plants have many other uses to man besides nutrition. 

 They offer to him material by means of which countless 

 needs are satisfied and many activities served. Every 

 part of the plant is used in one way or another. The hard 

 tissues which give support to the plant or serve as water 

 vessels find many uses. When they occur in bundles 

 in the stem or leaf they are extracted in long strands 

 (fibres) for use in making textiles and rope (flax, jute, 

 hemp. Sisal, etc.); whilst the large compact masses of 

 woody tissue of trees are utilised as timber. The soft 

 woods used for building are mainly from coniferous trees 

 (deal and larch), and the hard furniture woods from 

 dicotyledonous trees (mahogany, oak, walnut, rosewood, 

 beech, etc.). Many fibrous stems are utilised entire or 

 are merely split — e.g., canes and bamboos (for furniture, 

 etc.), straw (for hat-making), rushes and osiers (for 

 baskets), etc. Another use for the fibrous tissue is in 

 the manufacture of paper, for which purpose soft woods 

 (pine and spruce) and esparto-grass from North Africa 

 and Spain are now mainly employed; the better kinds of 

 paper, however, are made from old rags, which, of course, 

 were originally produced from vegetable fibres. 



Seed-hairs provided for the dispersal of seeds are 

 utilized in the case of cotton and kapok. Waste materials 

 and by-products formed by plants are turned to account 

 by man in the case of gums and resins, turpentine, rubber 

 and gutta-percha, dyestuffs, and tanning materials. 

 Food reserves in the plant are employed for industrial 

 purposes as well as for feeding man. Oil for making 

 paints and varnishes is extracted from linseed; for soap- 

 making, from oil-palm fruits, palm-kernels, dried coco- 

 nuts (copra), pea-nuts, sesame-seed, cotton-seed, and 

 many others; for illuminating, from rape and colza-seed, 

 etc.; and for lubricating, from castor-seed, etc. Starch 

 for dressing textiles and for laundry work, and for the 

 manufacture of glucose and industrial alcohol, is obtained 

 from potatoes, rice, etc. ; whilst the cellulose reserve of 

 the ivory-nut is used for making buttons. 



