280 



ECONOMIC BOTANY. 



■warm regions, as far North as 40° North Latitude (in 

 Crimea 45°), and as far South as 30° South Latitude. 

 Cotton consists of hairs on the seeds of several species of 

 Gossipyum, of the Mallow family (MalvacecB). The im- 

 portant species cultivated are : (1) G. herbaeeum, probably 

 indigenous in East Asia, cultivated in Turkey, Greece, 

 Asia Minor and India; (2) G. arboreum, a native of South 

 Asia, cultivated in East India, China, Egypt, West Indies, 

 and North America ; (3) G. hirsutum, native of West Indies 

 and Tropical America, and widely cultivated ; (4) G. barbor 

 dense, indigenous to West Indies, but cultivated in all 

 cotton-growing countries ; (5) G. religiosum, indigenous in 

 China, and cultivated in China, East Indies, etc. The 

 quality of the cotton depends somewhat on the species ; 

 that from the arboreous species is better than that from 

 the shrubby, and that from the shrubby, better than that 

 from the herbaceous species. The climate, soil, mode of 

 culture, etc., has also an influence on the quality of the 

 cotton as well as the habit of the plant. O. arboreum lives 

 fifteen to twenty years in its native country, and yields 

 annually two harvests. In Malta this species begins to fruit 

 the second year, and after two years of productivity dies. 

 The size and length of cotton of difierent species is as follows : 



The cell at first is round, and is more or less flattened 

 when dry, as is best shown in a transverse section (Fig. 

 349). The cell-wall is thicker than in most hairs, hence 



