300 
“2, CENCHRUS GRACILLIMUS 0. sp. 
Stems ascending or erect, 3-6 dm. high, simple or occasionally 
sparingly branched above, slender; sheaths smooth, striate, the 
lower overlapping, the upper shorter than internodes, 6-7 cm. 
long, but slightly inflated; leaves complanate, 5-8 cm. long, 
about 2 mm. broad, acuminate, scabrous on margins and mid- 
nerve; spike finally long-exserted, 3-5 cm. long, loosely 3-6 
flowered, internodes of scabrous rachis about I cm. long; in- 
volucre 2-flowered, smooth, ovate, purplish, deeply furrowed and 
smooth at base; spines purple, 5-6 mm. long, 1 mm. broad at 
base where they are sometimes ciliate, acutely barbulate at the 
apex; spikelets about 8 mm. long, exserted beyond involucre 
for one-third to one-half their length; Ist glume triangular, hya- 
line, acute, one-half as long as spikelet, strongly 1-nerved, slightly 
scabrous; 2d glume firm, ovate, acute, 7-nerved, scabrous ; 3d 
glume of firm texture, ovate-lanceolate, acuminate, slightly shorter 
than spikelet, 5-nerved, scabrous especially toward apex; 4th 
glume chartaceous, 7~8 mm. long, ovate-lanceolate, long-acumi- 
nate, strongly 5-nerved at apex, scabrous for upper half; palet of 
first flower equaling glume, strongly scabrous, 2-nerved, empty or 
enclosing three stamens; palet of perfect flower ovate, long-acu- 
minate, chartaceous, a little shorter than glume, 2-nerved, strongly 
scabrous toward apex; seed oblong, 2.5 mm. long, I.5 mm. 
broad. 
Florida, occurring in the high pine land, together with C. ¢7i- 
ulotdes and C. echinatus, flowering a little earlier than the former 
and later than the latter. It is readily distinguishable from either, 
especially when growing in the field, by its long slender purple 
spines, smooth involucre, very slender habit and closely compla- 
nate leaves. Begins to flower early in April. My Nos. 188 and 
288, collection of 1894.. 
3. CENCHRUS ECHINATUs L. Sp. Pl. 1050. 1753. 
‘ Stems creeping, erect, 3-6 dm. long, branching ; sheaths smooth, 
striate, inflated, lower ones overlapping, upper shorter than inter- 
nodes, 8-12 cm. long; leaves 1-4 dm. long, 5-15 mm. wide, smooth 
or scabrous, flat; spikes 4-12 cm. long, finally more or less €X- 
serted, very densely 20-50 flowered, internodes of the scabrous 
rachis 2-3 mm. long; involucre 4-6 flowered, globose, green to 
purplish, more or less pubescent, villous at base; spines 3-4 mm. 
long, barbulate at apex, more or less ciliate at base ; bristles at base 
of involucre numerous, slender, distinctly barbed for their whole 
length; spikelets 6-7 mm. long, more or less exserted from in- 
volucre; Ist glume hyaline, lanceolate, obtuse or acute, one-half 
as long as spikelet, strongly 1-nerved, sparingly scabrous at apex; 
