562 FLORA NIGRITIANA. 
16. Panicum sp., very near to the South African P. Linden- 
bergianum.—Setaria longiseta, Beauv., Kunth, Enum. 1. 
p. 158.—Fernando Po, Vogel. 
17. Panicum glaucum, Linn—On the Quorra, Vogel; and 
common almost all over the world. 
Taking the genus Panicum in its most comprehensive, as well 
as most definite form, so as to include Digitaria, Setaria 
and Echinochloa, there are now near 550 supposed species 
recorded by different writers. It is, however, now known, that 
a considerable number are spread over all the warmer parts of 
the globe, and have been described over and over again under 
different names ; and a careful revision and comparison would 
probably reduce the number under 300. Until this is done, 
the accurate determination of any but the best known species is 
next to impossible, nor has it been ascertained what are the 
distinctive characters most to be relied on, and how far they 
vary under cultivation. Nees von Esenbeck has, indeed, 
sketched out some excellent sections in his work on Cape 
Grasses, but has not applied them, in any published work, to 
the Panica of any other country. I fear, therefore, that some of 
the above determinations may not prove quite correct, and there 
remain 22 published West Tropical African species, which 
either are not in the collection before me, or I have been unable 
to recognise. These are: from Senegal, P. Perrottetii, Kunth., 
subalbidum, Kunth, raripilum, Kunth, and scabrum, Lam. ; 
from Sierra Leone, P. muscarium, Trin., lineatum, Trin., and 
tenellum, Lam. ; from Benin, P. setigerum, Beauv., and convo- 
lutum, Beauv. ; and from Guinea, P. regulare, Nees., P. pallide- 
fuscum, sphacelatum, cauda-ratti, subangustum, collare, serru- 
latum, longifolium, deflexum, sparsum, and plantagineum, 
Schum. et Thonn. ; and Digitaria reflexa, and D. nuda, Schum. 
et Thonn., also from Guinea. 
1. Thysanokena acarifera, N. ab E. Pl. Meyen, p. 181.—0n 
the Gambia, Boteler ; common in East India. 
1. Stenotaphrum Americanum, Schranck.—Kunth, Enum. 1, 
p. 138.—St. Thomas, Don; Guinea, South Africa and Tro- 
pical America. 
