62 GEOGRAPHICAL DISTRIBUTION 
following notes on the distribution of the more important genera, 
the tribes to which the latter belong will be found on reference to 
the chapter on Classification. 
We will consider the tropical genera first. Panicum is the 
largest ; nearly 800 supposed species have been published, but the 
number of fairly distinct species is probably not more than 250- 
300 ; they abound in all tropical and warm-temperate regions of 
the world. Andropogon, Aristida, Eragrostis and Stipa, each 
comprise about 100 species, abundant within the tropics; also 
found in temperate regions, more particularly of North America. 
The genera particularly numerous in America are: Paspalum, 
comprising 160 species, tropical or sub-tropical, the greater number 
American, not more than five belonging exclusively to the old 
world, and only two (introduced) in Southern Europe; Sforodolus, 
about 80 species, spread over the warmer and temperate regions 
both of the old and new worlds, mostly, however, American, few 
European or Asiatic; Muehlenbergia, nearly 60 species, chiefly 
American, extending from the Andes of South America over the 
northern continent generally, very few in Central or Eastern Asia ; 
Olyra, about 20 species, all tropical American with one exception, 
which is tropical African ; Bozztelowa, about 25 American species, 
northern or southern, but chiefly western. The genera most numer- 
ous in Africa are: Lanthonia, nearly 100 species, widely dispersed 
over the warmer regions of the world, the greater number, how- 
ever, South African ; Pennzse¢zm, about 40 species, chiefly African, 
of which two or three are dispersed over the Mediterranean region, 
tropical or sub-tropical Asia, or tropical America, a few endemic 
in Asia, Australia or tropical America ; Ekrharta, 24 species, of 
which 20 are South African, 2 in the Mascarene Islands, and 
2 in New Zealand. Chloris, Ischemum, Pappophorum, Chry- 
sopogon and Arundinella each comprise 20-40 species, dispersed 
over the warmer regions of both eastern and western hemispheres ; 
Pollinta comprises 25 tropical old-world species, with a few in 
extra-tropical Eastern Asia ; Erachne, 22 species, of which 20 are 
Australian (one of them occurring also in tropical Asia), the remain- 
ing two endemic in tropical Asia. 
The large genera of temperate regions are : Deyeuxia, nearly 120 
species, dispersed over the temperate or mountain regions of the 
globe, particularly numerous in the Andes of South America, 
extending northward to the Arctic circle and southward to the 
Patagonian peninsula; Festuca, about 80 well-defined species 
(some botanists have made over 230), almost universally distri- 
buted, but most abundant in the northern temperate regions of 
the old world, with not many American or tropical species; Poa 
is another cosmopolitan genus of about 80 species (they have been 
estimated by some authors at over 200), particularly abundant in 
the northern hemisphere and sparingly represented within the 
tropics ; Agrostz7s, 100 species, very widely dispersed, especially 
common in the temperate regions of the northern hemisphere, 
some almost cosmopolitan. Spread over the temperate or colder 
