330 



BOTANY AND PHARMACOGNOSY. 



also in Northern Africa, Brazil, Peru and Queensland. This spe- 

 cies is distinguished by the fact that after removal of the hairs 

 from the seeds they are smooth. (2) G. arhorcuui has purplish- 

 red flowers, yields a particularly white cotton, and is cultivated 

 in Egypt, Arabia and India. (3) G. hcrbaccuin is distinguished 

 by its broadly lobed leaves and yellowish flowers. The plant has 



Fig. 166. Transverse (t) and longitudinal (1) sections of commercial fibers: A, long 

 staple cotton from the seeds of Gossyphttn; B, Kentucky hemp, the bast of Cannabis 

 saliva; C, jute, the bast of Corchorus; t). sisal, the fibers from the leaves of the Century 

 plant {Agave rigida Sisalana) ; E, raphia. the outer layers of leaflets of Raphia pedunculata; 

 F. ramie, the fibers from a Formosa nettle; G, Merino wool; H, silk; I, artificial silk, the 

 figure on the left showing a false lumen due to the infolding of the edges, f. fungal hyphae; 

 c, rosette aggregates of calcium oxalate; p. parenchyma cells. 



been cultivated for over 26 centuries in Arabia and the East 

 Indies, and since 1774 in the United States. Of this latter species 

 there are a number of cultivated varieties. The bark of the root 

 constitutes the cotton-root bark of medicine (p. 527). 



The seeds of the genus Gossypium contain a large percentage 

 of fixed oil. which is obtained by expression and is official as 



