500 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 1962 



seasonal drought has been much more successful with annual cottons. 

 Consequently the development of annual types has made possible vast 

 extensions of the area in which the plant can grow, and the subdivi- 

 sions that have arisen in each of the cultivated species are best de- 

 scribed as geographical races. In the cottons of the Old World, 

 annual forms were first develox^ed in G. herhaceum (fig. 1). In 

 this species the most primitive, and only truly wild, form is race 

 africanum', this is a perennial shrub found on the southern African 

 bushveld across a belt of country from Mozambique to Angola and 

 southwest Africa [18]. The most primitive cultivated forms are 

 those found as occasional perennial plants in fields and gardens in 

 Ethiopia [21], in southern Arabia, and on the coasts of southern 

 Baluchistan; these are included in the race acerifolium. Inland in 

 Iran, a characteristic group of annual forms has arisen, named race 

 persicum. Farther north, where the summers are shorter and the 

 winters colder, the species has given rise, by progressive adaptation 

 to shorter seasons, to the huljianum cottons of Central Asia that will 

 mature a small crop in three months from sowing. The annual 

 persicum cottons from Iran spread into western India, and provided 

 the first annual cottons in Indian agriculture. The introduction can 

 be dated, since it has been shown [19] that when Dr. Hove collected in 



^;> 



S>v£^ §. 



"27^ 



/ . 



\ ( • ■ G. arboreum 



G. herbaceum 

 africanum 



indicum 



^K::^^.. 



D 



^ 



Figure 1. — Distribution of the Old World cottons at time of Marco Polo (13th century). 



