564 FLORA NIGRITIANA. 
even nearly a line long, the upper one mucronate or very shortly 
awned, the neutral flower reduced to one palea, the styles free, 
and in this, as in some other Penniseta, I have occasionally 
observed three of them instead of two. 
3. Pennisetum gracile, Benth.; glabrum, ramosum, folis an- 
gustis scabriusculis, spica tenui, spiculis solitariis, involucri 
setis exterioribus paucis interioribusque plumosis pluribus 
spieulam subsuperantibus, una longissima, flore masculo 
bipaleaceo, palea exteriore glumaque superiore 5-nervibus.— 
Sierra Leone, Don. 
Culmi basi decumbentes, ramis suberectis vix semipedalibus. 
Spica tenuis, 1}-2-pollicaris, purpurascens. Rhachis glabra. 
Spicule glabre v. apice scabro-puberule. Gluma exterior 
nulla v. minutissima, superior uti palea exterior floris mas- 
culi apice mucronata. 
The P. violaceum, Rich., and P. Prieuri, Kunth., both from 
Senegal, appear to be different from either of the above. 
l. Cenchrus echinatus, Linn.—Kunth, Enum. 1. p. 166.—On 
the Gambia, Don ; South America, Africa and East India. 
Another species, C. barbatus, Schum. et Thonn., is described 
from Guinea. i 
The Lappago racemosa, Willd., common over a great part of 
the globe, is also found in Senegal. The Latipes Senegalensis, 
Kunth, from Senegal, is unknown to me. Six species of Aris- 
tida are said to be found in West Tropical Africa, none of which 
are in the collection. They are: A. s/ipeformis, Lam., hor- 
deacea, Kunth, and festucoides, Poir., from Senegal; and 4. 
submucronata, cerulescens and longiflora, Schum. et Thonn., 
from Guinea, but probably some of the three latter may be 
repetitions of the others. 
l. Sporobolus. virginicus, Kunth, Enum. 1. p. 210, forma 
parvula, glumis levissimis v. vix ad. carinam scabriusculis.— 
St. Thomas, Don, a common maritime plant in America and. 
Africa. 
9. Sporobolus robustus, Kunth, Enum. 1. p. 213,—Grand 
Bassa, in marshes, where it is gregarious, and attains six oF 
eight feet in height, Vogel ; Cape Verd Isles, Ansell ; Ga- 
