Economic Importance of Plants 261 



Straw, which is the stalk, leaves, etc., of wheat, oats, rye, barley, and 

 rice, is used for making hats, mats, baskets, paper, pasteboard, etc. 



The ripened branches of the flower cluster of broom corn (grass fam- 

 ily) yields a flexible, tough material from which various kinds of brooms 

 are made. 



The fibers split from the stems of rattan (palm family) are called reeds 

 and are used in making baskets, cane seats, wickerware, coarse brushes, 

 etc. The stems of the bamboo (grass family) are used quite extensively 

 for various purposes. The fibers from the leaves and nut husks of the 

 coconut palm (palm family) are used in the manufacture of door mats, 

 cables, etc. Punk is a mass of slender fibers found within the rind of 

 certain shelf fungi. It is used to stop bleeding in dentistry, as tinder to 

 kindle fires, for making mats, etc. 



Cork. — Cork is a light, compressible, nonfibrous, waterproof mate- 

 rial secured from the outer bark of the cork oak (beech family). It 

 contains about 75 per cent of a tallowlike, waxy substance known as 

 suberin. The pores of the cork are channels through which air may 

 enter the plant. The cork grows in layers, and unless the outer lay- 

 ers are carefully removed at certain intervals, the product is inferior. 

 Slabs of cork of various thickness may be removed about every eight 

 years, with the result that abundant quantities of homogeneous cork are 

 obtained. The removal of this cork does not injure the tree; in fact, re- 

 moval seems to be beneficial to it. There are many uses for cork, but 

 the following are typical: floor coverings, lining for shoes and hats, stop- 

 pers, packing for fruits, and the making of artificial limbs, life preservers 

 and fish-net floats. 



Woods. — Wood is a comparatively hard mass of fibrous material 

 cemented together and contains, in addition to the common substance 

 cellulose, more or less of the substance lignin. The lignin is of unknown 

 chemical composition, although it is similar to cellulose. The cellulose 

 is distinguished from lignin by turning blue instead of yellow when 

 treated with sulfuric acid and iodine. 



The texture, strength, durability, and hardness of woods depend on 

 the arrangement of the various materials of which the diff"erent varieties 

 are composed. 



The following are a few typical and representative uses of wood: 

 wood pulp from certain trees, such as poplar and spruce, is used in the 

 manufacture of paper; certain woods as spruce and white pine are 

 shredded into excelsior; splints split from such hard woods as hickory 

 and ash, which split easily, are used in making baskets and similar ob- 



