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. arboreum has purplish- 

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

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

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



Fig. 166. Cotton plant (Gossypium): A, dehiscent capsule showing mass of cotton 

 fibers which surround the small seeds; B, leaf- branch; C, large axillary flower. 



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 



