POACEAE 
86 
summit, [C. caudata p has been eolleeted on ballast at Mobile, Ala. 
Nat. of S. A.—(W. I., Mex., S. A.) 
PENNISETUM L. C. Rich. Annuals or perennials, often branched 
itary or in groups of 2 or 
Spikelets solitary or in g 
34. 
with dense spike-like terminal panieles 
3 surrounded by an involuere of slender bristles, these not united except at the 
very base, often plumose, falling attached to the spikelets; glumes shorter than 
the sterile and fertile lemmas; fertile lemma chartaeeous, smooth, the margin 
thin, enclosing the palea.—Fifty species, natives of the tropical regions 
Bristles, at nas 29r exceeding the spikelets, the large caryopsis dde througn 
ucum. 
2. P. setosum. 
the lemma and pal 
Bristles much exceeding the spikelets, the earyopsis remaining within 
or even more: 
e lemma and p 
Lr: A e R. Br. oru pipe 1-3 m. tal 
blades 40 em. long and 4 em. wide: panicle pod dis dense, ie 
like, ER 10- —30 em. long, 1-1. 5 cm. in ee 
diameter bic pci spicata Willd.]— QOO Ad 
(PEARL-MILLET.)—Cult. grounds and road- SR Pa 
E various va utt dos to Md. DE coe 
Nat. of Afr.—Cult. for for IPM SN 
OR EL ES 
2. P. setosum (Swartz) L. C. Rieh. Stem Soc? 
1-1.5 m. tall: leaf- bs 5-10 mm. wide: do VUE : 
paniele 10—15 = ong, Ns rng above, CANE ET : 
usually purple: er bristles about as long Sg aD 
as spikelets, dins inner ; bristle es ee N bs FEE C! 
densely silky-plumose on lower par Pei 
a = the others: spikelets ee 3 Wee 
mm. long.—Sandy soil, S Fla.—(W. I. AU 
. 4. ) HE 
flat 
M ez., P As 
35. CENCHRUS L. Low branching annuals or perennials, with 
u urs. Spikelets solitary or 
sed of several 
and thick, articulate at ing w the s 
in ours retrorsely bar Pu S cn -five species, in warm 
most abundant in America.—SAND-BURS. BUR-GRASSES. 
few together, surroun 
coaleseing bristles (sterile penis the bur ie dan 
with spik Fac en 
re 
SAND-SPURS. 
SPURS. 
Involucral lobes united below: stem compressed, branched, the branches usually de- 
I. TRIBULOIDES. 
II. MIO ODE 
cumbent and spreading. 
Involueral lobes united at the base only: stem terete 
RIBULOIDES 
Involucre with a ring of slender bricties at base. 
Burs ree E bristles not over 4 mm. wide, numerous, 
crow es ~ a long spike; lobes of the involucre inter- 
locking 1. C. viridis. 
Burs excluding bristl -7 mm. wide, not densely crowded ; 
s of the inv pcre erect. 2. C. echinatus. 
involucre witli ee spreading spines, no ring of slender 
bristles at 
stems rather slender and 
plants per- 
Burs eaperne ers base, ovate: 
iry, fs ascending or erect, 30-60 cm. tall: 
a 
