THE PRINCIPAL SPECIES OF COTTON 31 



in this genus are characterized by possessing erect branch- 

 ing stems. The leaves are petioled and palmately lobed. 

 The flowers are showy. There are five sepals united into 

 a cup-like calyx; also five petals, of whitish or yellowish 

 color, often turning pink. The seeds are angular and 

 wooly, or, more rarely, naked. In this genus the stigmas 

 grow together and usually number from three to five, 

 according to the number of locks that will be contained in 

 the matiu-e boll. 



35. Number of species. — There has been much dif- 

 ference of opinion among botanists as to the number of 

 species composing the genus Gossypium. Watt, in "The 

 Wild and Cultivated Cotton Plants of the World" describes 

 29 species of cotton, many of which have never been re- 

 corded as seen under cultivation. Duggar ^ states that as 

 many as fifty-four species of Gossypium have been de- 

 scribed, most botanists, however, reducing the species 

 to a much smaller number. It is quite possible that, as 

 a resulf of modification due to hybridization and climatic 

 factors, names of species have in many cases been need- 

 lessly multiplied. 



Much confusion has also been caused as a result of mis- 

 naming species. For example, American upland cotton, 

 {Gossypium hirsutum) has frequently been referred by 

 American authors to Gossypium herbaceum, a species of 

 Asiatic cotton. Recent studies have shown these two 

 species .to be quite dissimilar. 



36. Classification of species. — The large number 

 of both wild and cultivated species of cotton is classified 

 by Watt ^ into five sections. This classification is based 

 largely on the following characters: (1) the position and 



1 Duggar, J. F., " Southern Field Crops," p. 275. 



2 Watt, " The Wild and Cultivated Cotton Plants of the World." 



