POACEAE 65 
23. Andropogon Tennesseénsis Scribn. Stems 1-1.5 m. tall, stout, the branches 
in 1’s or 2’s: leaf-sheaths, at least the lower ones, hirsute toward the summit ; blades 6 
dm. long or less, 6-12 mm. wide, rough, the lower surface sometimes hirsute, and also the 
upper surface near the base: racemes in 2’s—4’s, 5-8 cm. long: sessile spikelet about 8.5 
mm. long, broadly lanceolate, twice as long as the hispidulous internode, the outer 2 
scales strongly hispidulous, the awn of the fourth scale geniculate, about 1.5 cm. long, 
twisted below, the column a little exserted ; pedicellate spikelet 8-10 mm. long, of 4 scales, 
perfect, the outer 2 scales strongly hispidulous, the first often short-awned, the hispidulous 
pedicel less than 4 as long as the sessile spikelet. 
In dry soil, Tennessee and Mississippi. Fall. 
24. Andropogon geminatus Hack. Smooth and glabrous, glaucous. Stems 6-10 
dm. tall, from long rootstocks: leaf-blades erect, rigid, long-acuminate, 3 dm. long or 
less, 9 mm. wide or less: racemes in pairs, finally exserted, 3-5 cm. long, rather slender, 
the hairs on the rachis-internodes and the pedicels grayish or yellowish white: sessile 
spikelet 6-8 mm. long, the awn not twisted below, geniculate, 5-7 mm. long; pedicellate 
spikelet about the same length, awnless. 
In dry soil, Texas. Summer. 
10. AMPHILÓPHIS Nash.’ 
Perennial grasses, with usually flat leaf-blades and showy often silvery white panicles, 
the axis short, making the panicle appear fan-like, or elongated with the branches scattered. 
Racemes usually numerous, the internodes with manifestly thickened margins, the median 
portion thin and translucent, the pedicels of the same construction, the margins ciliate 
with usually long hairs. Sessile spikelets,of 4 scales, the first one 2-keeled, the second 
l-keeled, the third and fourth scales hyaline, the latter very narrow, stipe-like, somewhat 
thickened, gradually merging into a usually geniculate contorted or spiral awn, or the awn 
rarely wanting.  Pedicellate spikelets staminate and similar to the sessile, or sterile and 
smaller than them. Stamens 3. Styles distinct. Stigmas plumose. 
First scale of the sessile spikelet not pitted on the back. : ; 
Axis of the panicle elongated, the branches scattered, the panicle hence linear 
to oblong ; stem-nodes naked. ^ 
Sessile spikelets 3 mm. long, the awn wanting or rarely present and then but 2 
short and not twisted. ; : 1. A. exaristatus. 
Sessile spikelets 4 mm. long, the awn long and geniculate, spiral at the base. 2. A. Torreyanus. 
Axis of the panicle short, the branches congested, the panicle hence fan-like, ; : 
: oval or obovate; stem-nodes densely barbed. | ` 3. A. barbinodis. 
First scale of the sessile spikelet with a deep pit-like impression on the back. 4. A. perforat us. 
1. Amphilophis exaristatus Nash. Smooth and glabrous. Stems 6-8 dm. tall, rather 
slender: leaf-blades 2 dm. long or less, 3-6 mm. wide, rough toward the apex: panicle 
10-13 em. long, 2-2.5 em. wide, oblong, its axis 8-10 em. long, the branches much divided, 
the ultimate divisions (racemes) 1-2 cm. long, the terminal hairs 2-3 times as long as the 
rachis-internodes: sessile spikelet 3 mm. long, about j again as long as the internode, 
the fourth scale almost wanting, or present as a mere rudiment, very rarely short-awned ; 
pedicellate spikelet of a single scale, 2-3 mm. long, the pedicel considerably shorter than 
the sessile spikelet. [Andropogon saecharoides submuticus Vasey, not A. submuticus Steud. ] 
In dry soil, Texas. Summer. 
2. Amphilophis Torreyanus (Steud. ) Nash. Smooth and glabrous, glaucous. Stems 
5-10 dm. tall, simple or somewhat branched : leaf-blades 1-5 dm. long or less, 3-7 mm. 
wide, rough above : panicle 4-10 cm. long, 7-20 mm. wide, linear to oblong, its axis 2-7 
em. long, the longer branches somewhat divided, the ultimate divisions ( racemes) 1-4 cm. 
long, the terminal hairs 14-2 times as long as_ the internodes: sessile spikelet 4 mm. long, 
about 3 again as long as the internode, the awn geniculate, more or less contorted, 10-15 
mm. long, spiral at the base, the column much exserted ; pedicellate spikelet consisting of 
a single scale, 2-3 mm. long, the pedicel shorter than the sessile spikelet. 
In dry soil, Kansas to Arizona, Texas and Mexico. Summer, : 
3. Amphilophis barbinódis (Lag.) Nash. Stems tufted, 5-10 dm. tall, simple or 
somewhat branched, the nodes densely barbed with silvery hairs: leaf-sheaths and their 
blades smooth and glabrous, the latter 2 dm. long or less, 2-8 mm. wide, rough : panicle 
broadly oblong, ovate, oval or obovate, 5-12 cm. long, finally exserted, its axis 2-5 em. 
long: racemes 2-15, 3-5 cm. long, the terminal hairs twice as long as the internodes: ses- 
sile spikelet 5-6 mm. long, about } again as long as the internode, the geniculate awn 
2-3 cm. long, spiral at the base, the column much exserted ; pedicellate spikelet of a single 
awnless scale, 4-5 mm. long, the pedicel considerably shorter than the sessile spikelet. 
In moist or rocky ground, central Texas to Arizona and Mexico. Summer and fall, 
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