122 ELEMENTARY BOTANY. 



6. The Camphor tree, Laurus camphora, is an evergreen of 

 Eastern Asia. It resembles the Linden tree, but is evergreen, 

 and belongs to the Laurel family. The Camphor is obtained 

 from the twigs by sublimation. It is used in pyrotechnics 

 and in medicine. The Starch of commerce is derived from 

 bulbs, tubers, seeds, etc. The most important starch-pro- 

 ducing plants are the Potato, Wheat, Rice, Corn, the East In- 

 dian Arrow-root, and the West Indian Arrow-root. A plant, 

 Manihot utilissima (Spurge family), indigenous to tropical Amer- 

 ica, but cultivated in many tropical lands, furnishes the Bra- 

 zilan Arrow-root, Cassava and Tapioca. The large fleshy 

 parsnip-like root is poisonous in the natural state. It is 

 peeled and washed carefully, thus removing the poisonous 

 material ; the ground mass is called Cassava. The starch is 

 moistened, granulated by means of sieves and heated on metal 

 plates to make Tapioca. The quantity of Sugar used annu- 

 ally is enormous ; the largest portion is obtained from Suga,r- 

 cane and from the Sugar-beet. The Maple tree and Sorghum 

 also furnish a considerable quantity. 



7. The various vegetable Fibres used in the manufacture 

 of fabrics, cordage, paper, etc., constitute a class of products 

 of great importance. They may be vegetable hairs, as cotton, 

 silk cotton, etc. ; woody strands (fibro-vascular bundles) from 

 Monocotyls, as New Zealand flax, Manila hemp, etc. ; or they 

 may be parts (the bast) of fibro-vascular bundles from Dico- 

 tyls, as Hemp, Flax, Jute, etc. Most fibres are white or whit- 

 ish in color; others may be gray or yellowish. They are 

 composed almost exclusively of cellulose ; occasionally they 

 are partially lignified, and then are brittle. For cordage (ropes, 

 cables, strings) the fibres may be coarse but they must be strong 

 and not break when bent at a sharp angle. Those for cables 

 must, besides, be capable of absorbing tar. The fibres for 

 yarns must be of considerable length, fineness and strength. 

 They must be glossy, or possess the " spinning quality." For 

 faper they must be thin and strong, and suitable for felting 

 together when wet. A curly disposition so as to catch each 

 other and become entangled, gives tenacity to the paper ; this 



