THE NORTH AMERICAN SPECIES OF CHJITOCHLOA. 



INTRODUCTION. 



The North American species of Chcetochloa have long been unsatis- 

 factorily identified, and the present revision is offered in the hope of 

 clearing up much of the existing confusion in this genus. It was at 

 first proposed to consider only those species native of or introduced 

 into the United States, but as the Mexican and West Indian species 

 were found to be in an even more unsatisfactory condition than those 

 of the United States, it seemed advisable to include such of these 

 species as were represented in the material at hand. 



In North America there are 28 species of Chcetochloa^ 6 of which 

 are here published for the first time. Of these 28 species, 23 are 

 native of North America, the remaining 5 having been introduced from 

 Europe, of which 3 are cosmopolitan weeds found in the temperate 

 regions of both hemispheres. 



From an economic standpoint the genus takes high rank through the 

 extensive cultivation of C. italica,, various forms of which, under the 

 names of millet, Hungarian grass, etc., are widely cultivated in this 

 country as soiling or forage crops, and are among the oldest cultivated 

 crops of the world, record having been found of its cultivation in China 

 as early as 2700 B. C. In Europe its cultivation dates from prehistoric 

 times, as the grain is found in abundance in the debris of the Lake 

 Dwellings of the Stone Age in Switzerland. 



The species are for the most part readily distinguished, except in 

 the group represented by C. imherbis^ which is extremely variable and 

 is found in the warmer regions in both hemispheres. In general the 

 details of the spikelets in this group are very similar, the variation 

 being chiefly in the length and color of the panicles and setifi and in 

 the vegetative characters. C. gracilis and C. purpurascetis are here 

 recognized as valid species, as they have certain constant characters by 

 which they can be readily distinguished from related species. C 

 inacrostacliya., originally described from Mexican material and since 

 credited to Asia and Australia, is confined to America, the Asiatic 

 forms referred to this species are now referred to Ch^tochloa for- 

 BESIANA (Nees) n. comb. {Panicwn fovhesianum Nees) and the Aus- 

 tralian form, which is very distinct from C. macrostachija, is here 

 proposed as a new species. C composita^ a common southwestern 



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