60 POACEAE 
9. Schizachyrium triaristàtum Nash. Stems 6-8 dm. tall, stoloniferous: leaf- 
sheaths keeled, more or less hirsute on the margins near the summit ; blades 1.5 dm. long 
or less, 3-5 mm. wide, hirsute above near the base: racemes single, 3-5 cm. long: sessile 
spikelet 9-10 mm. Jong, acuminate, more than twice as long as the rachis-internode, the 
first scale smooth or nearly so, the awn of the fourth scale 12-15 mm. long, geniculate, 
more or less contorted, spiral at the base, the column not exserted ; pedicellate spikelet of 
2 scales, 6-8 mm. long, the first scale hispidulous, 3-awned. 
In sand, Florida. Fall. 
10. Schizachyrium gracile (Spreng.) Nash. Smoothand glabrous. Stems densely 
tufted, slender, rigid, 3-6 dm. tall; leaf-blades 2 dm. long or less, very slender, involute, 
0.5 mm. in diameter or less: racemes long-exserted, single, 3-5 cm. long, silvery white : 
sessile spikelet 5-6 mm. long, about 4 again as long as the internode, the awn geniculate, 
13-20 mm. long, tightly spiral to the bend, loosely so above, the column much exserted : 
pedicellate spikelet consisting of a single scale, 1-2.5 mm. long, short-awned, the pedicel 
about as long as or a little shorter than the sessile spikelet. [Andropogon gracilis Spreng. ] 
In dry pine woods, southern peninsular Florida: also in the West Indies. Summer. 
9. ANDROPOGON L. 
Perennial grasses, tufted or from elongated rootstocks, with flat or involute leaf-blades, 
and spike-like racemes, disposed in pairs or sometimes in 3’s or more, terminating the stem 
or its branches, and often protruding from the side of a membranous spathe-like sheath. 
Spikelets sometimes with a ring of short hairs at the base, in pairs at each node of the 
articulated and frequently hairy rachis, one sessile, the other pedicellate. Sessile spikelet 
of 4 scales, the outer 2 indurated, often pubescent, the remainder of the scales usually 
hyaline, the fourth scale entire or 2-toothed at the apex, bearing a straight contorted or 
spiral awn, or sometimes awnless ; palet small, hyaline. Pedicellate spikelet usually sterile 
of 1 or 2 scales, sometimes of four scales and enclosing a staminate or more rarely a perfect 
flower, or frequently entirely wanting, the first scale rarely short-awned. Stamens 1-3. 
Styles distinct. Stigmas plumose. BEARD Grass. Broom Grass. SAND GRASS. 
A. Pedicellate spikelet sterile, consisting of 1 or 2 scales, much smaller than the 
sessile one. 
a. Stamen 1. i 
1. Racemes usually equalling or a little shorter than the spathes, rarely 
somewhat exceeding them (considerably exserted in some forms of 
no. 2), the common peduncle thus concealed. 
Inflorescence oblong to oval or obovate, the branches many times di- 
vided, the lower ones elongated, forming 1 or more corymbiform 
masses; upper stem-leaves usually equalling or exceeding the in- 
florescence. 
Spathes smooth; apex of the common peduncle of the racemes gla- 
brous. 1. A. glomeratus. 
Spathes very rough ; apex of the common peduncle of the racemes 
hispidulous. 2. A. corymbosus. 
Inflorescence long and narrow, commonly linear, the branches not 
much divided nor the lower ones excessively elongated, hence 
forming no corymbiform masses ; upper stem-leaves usually shorter 
than the inflorescence. 
Racemes in pairs (very rarely in 3’s or 4’s). 
Sheaths not glabrous. 
Sheaths hirsute on the margins, the upper surface of the leaf- 
blades also hirsute near the base; hairs on the summit of 
the internodes of the racemes rather sparse, and about 
twice their length, 3. A. Virginicus. 
Sheaths, especially those of the innovations and their blades, 
densely appressed-hirsute; hairs on the summit of the 
internodes of the racemes copious and about three times 
their length. 4. A. longiberbis. 
Sheaths glabrous. 
Leaf-blades tuberculate-hirsute above toward the base; hairs 
of xs racemes dense, the spikelets therefore obscurely 
visible. 
Leaf-blades not hirsute above; hairs of the racemes rather 
scant, the spikelets therefore plainly visible. 
Branches of the inflorescence several times divided : spathes 
2-3 em. long. 6. A. capillipes. 
Branches of the inflorescence simple: spathes 4-7 em. long. 
Stems slender; basal leaf-blades narrow, 2 mm. wide or 
Jess, usually long and flexuous. 7. A. perangustatus. 
Stems cha basal leaf-blades broad and rigid, 3-6 mm. 
c 
(A. Tracyt: 
wide. 8. A. glaucopsis. 
Racemes in 4's (rarely in 2’s or 3’s) ; sheaths, at least the lower ones, 
densely hirsute. 
