136 POACEAE 
the lower ones subverticillate. Spikelets 1-flowered, narrow, sessile or nearly so, scattered, 
appressed, the rachilla glabrous and prolonged beyond the flower, bearing at its apex a 
small usually awned scale. Scales 4, the 2 lower empty, persistent, narrow, acute, or the 
second short-awned, the third scale somewhat broader, shortly 2-toothed at the apex, bear- 
ing a straight awn, and enclosing a narrow 2-keeled palet and a perfect flower ; fourth scale 
empty, awned, the body often much reduced. Stamens3. Styles distinct. Stigmas plu- 
mose. 
Spikes spikelet-bearing their whole length : awn longer than the flowering scale. 1. G. ambiguus. 
Spikes spikelet-bearing only above the middle: awn shorter than the flowering scale. 2. G. brevifolius. 
1. Gymnopogon ambíguus (Michx.) B.S.P. Stems 3-5 dm. tall, erect, or decum- 
bent at the base : leaf-sheaths with a villous ring at the summit, crowded at the base of the 
stem ; blades 2-10 cm. long, 4-12 mm. wide, lanceolate, crowded at the base, spreading : 
spikes slender, the lower ones finally widely spreading, 1-2 dm. long: spikelets, exclusive 
of the awn, 4—5 mm. long, the awn of the flowering scale 4-6 mm. long. [G. racemosus 
Beauv. | 
In dry sandy soil, southern New Jersey to Missouri, Florida and Texas. Summer and fall. 
2. Gymnopogon brevifdlius Trin. Stems 3-6 dm. long, decumbent at the base, 
slender : leaf-sheaths sometimes crowded at the middle of the stem ; blades 2-5 cm. long, 
2-8 mm. wide, lanceolate, usually spreading : spikes very slender, the lower one finally 
widely spreading and 1-1.5 dm. long: spikelets, exclusive of the awn, 3 mm. long, the 
flowering scale short-awned. 
In dry soil, New Jersey to Florida and Mississippi. Summer and fall. 
82. SCHEDONNARDUS Steud. 
Annual grasses, with narrow almost subulate leaf-blades and an inflorescence consisting 
of numerous long slender spikes arranged in an open panicle. Spikelets 1-flowered, acumi- 
nate, scattered, appressed, sessile and alternate on opposite sides of the rachis. Scales 3, 
membranous, the 2 lower empty, persistent, narrow, acuminate, somewhat unequal, the 
third scale longer, at length rigid, enclosing a narrow shorter palet and a perfect flower. 
Stamens 3. Styles distinct. Stigmas plumose. 
1. Schedonnardus paniculàtus ( Nutt.) Trelease. Stems 2—5 dm. tall, slender, erect, 
rigid, branched at the base: leaf-sheaths crowded at the base ofthe stem, compressed ; 
blades 2-5 em. long, 2 mm. wide or less, usually erect, flat: spikes numerous, widely spread- 
ing, alternate, rigid, the lower ones 5-10 em. long : spikelets 2.5-3 mm. long, appressed, 
alternate. 
In dry soil, Manitoba and Assiniboia to Illinois, Texas and New Mexico. Summer and fall. 
83. BOUTELOUA Lag. 
Annual or perennial grasses, with narrow flat or convolute leaf-blades, and an inflores- 
cence composed of few scattered one-sided, often more or less curved, many-flowered sessile 
spikes with the rachis sometimes conspicuously prolonged beyond the spikelets. Spikelets 
numerous, 1-2-flowered, the lower flower perfect, the upper one when present staminate or 
sterile, crowded in 2 rows. Scales 3 or more, the 2 lower empty, narrow, acute, un- 
equal, keeled, the third one enclosing a narrow hyaline palet and a perfect flower, usually 
thinner and broader, 3-nerved, the nerves excurrent from the lobes or teeth as short pro- 
jections or awns or protruding between the lobes, the small empty scales terminating the 
rachilla 1-3, 3-awned. Stamens 3. Styles distinct. Stigmasplumose. MESQUITE GRASS. 
Awns terminating the lobes of the flowering scale. 
Stems glabrous. 
Rachilla of the spikelet with a dense tuft of long hairs at the apex. 1. B. oligostachya. 
Rachilla glabrous. 
Second empty seale with large hair-bearing tubereles on one or both sides 
of the midnerve. 2. B. hirsuta. 
Second empty scale glabrous and free of tubercles. 
Flowering scale pubescent with long ascending silky hairs. 3. B. Burkei. 
Flowering scale glabrous, or sometimes with a few hairs at the base. 4. B. trifida. 
Stems densely villous below. 5. B. eriopoda. 
Awns arising between the lobes of the flowering scale. 6. B. microstachys. 
1. Bouteloua oligostáchya (Nutt.) Torr. Stems 1.5-5 dm. tall, erect : leaf-blades 
2-10 cm. long, 2 mm. wide or less, involute, at least at the long slender point : spikes 1-5, 
2.5-5 cm. long, the rachis ending in a short inconspicuous tip: spikelets about 6 mm. long, 
the rachilla with a tuft of long hairs under the rudimentary scales and awns. 
On prairies, Manitoba to Alberta, Wiseonsin and Texas. Alsoin Mexico. Summer and fall. 
