1_> GRAMINEAE (GRASS FAMILY) 



placed flatwise on the rachia 62. Agropyron. 



r more at each joint of the rachis. 



:l..w,Tl 63 ' Hordeum. 



Spik.-1.-t> _' many-flowered. 



EUohta .-..ntinuous 64 - Elymus. 



,-i.lily separating into joints 65. Sitanion. 



1. ANDROPOGON L. BEARD GRASS OR BLUE-STEM 



Perennials, usually with long narrow leaves, and terminal and axillary 

 racemes Spikelets in pairs at each node of the jointed hairy rachis, one sessile 

 and perfect, the outer with a pedicel and either staminate, empty, or reduced 

 to a siimle glume. Perfect spikelet consisting of 4 glumes; the outer 2 coriaceous, 

 on.l keeled and acute; the two inner hyaline, the fourth more or less 

 awned and subtending a palet and perfect flower. Stamens 1-3. Grain free. 



Racemes solitary, distinct, 1-3 at each node 1. A. scoparius. 



Karrmrs in pairs or approximate. 



Awn loosely spiral, geniculate 2. A. furcatus. 



Awn straight or sometimes wanting 6. A. Hallii. 



1. Andropogon scoparius Michx. Fl. Bor. Am. 1: 57. 1803. Culms tufted, 

 6-12 dm. tall: sheaths sometimes glaucous: leaves 15-30 cm. long, scabrous: 

 spikes 25-50 mm. long, loose, distinct, and 1-3 at each node, on long-exserted 

 slender peduncles: rachis slender, flexuous; joints and pedicels ciliate with long 

 spreading hairs: outermost glume of sessile spikelet about 6 mm. long; awn 

 spiral, 10-12 mm. long; pediceled spikelet a single awn-pointed glume. Dry, 

 sandy soil; throughout our range. 



2. Andropogon furcatus Muhl. Willd. Sp. PI. 4: 919. 1806. Culms stout, 

 9-18 dm. tall: sheaths smooth and glabrous: leaves 15-45 cm. long: spikes 2-5, 

 in pairs or approximate, 5-10 cm. long; joints of the rachis and pedicels 

 ciliate with short hairs: outermost glume of sessile spikelet 6-8 mm. long; awn 

 of the sterile lemma loosely spiral, geniculate, 10-14 mm. long; pediceled 

 spikeht of 4 glumes. Eastern part of our range and eastward. 



3. Andropogon Hallii Hack. Sitz. Akad. Wiss. Wien 89: 127. 1884. Culms 

 robust, 9-18 dm. tall, more or less glaucous: sheaths somewhat glaucous: 

 leaves 3 dm. long or less: spikes 2-5, in pairs or approximate, 5-10 cm. long: 

 joints of the rachis and pedicels villous with long hairs: outermost glume of 

 sessile spikelet about 8 mm. long, acuminate, glabrous at base, from sparingly 

 to copiously silky-pubescent toward the apex; awn of the sterile lemma 

 straight, 4-10 mm. long, or sometimes wanting; pediceled spikelet consisting 

 of 4 glumes, generally larger than the sessile spikelet and inclosing three 

 stamens. Dry, sandy soil of the plains and foothills; along the eastern border 

 of the Rocky Mountains. 



2. AMPHILOPHIS Nash 



Perennials, usually with flat leaves and showy, often silvery-white panicles, 

 the axis short, making the panicle appear fan-like, or elongated with the 

 1. ranches more scattered. Racemes usually numerous, the internodes with 

 manifestly thickened margins, the median portion thin and translucent; the 

 pedicels of the same structure, the margins ciliate with long hairs. Sessile 

 -pikelets of 1 glumes, the first one 2-keeled, the second 1-keeled, the lemmas 

 hyaline, i he 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 -mailer. Stamens 3. Styles distinct; stigmas plumose. Grain free, in- 

 in the lemmas. 



1. Amphilophis Torreyanus (Steud.) Nash, Brit. Man. 71. 1901. Culms 



i 10 dm. tall, the nodes naked: sheaths more or less glaucous: leaves 



7 17 cm. long, glaucous: spikes '_'."> :if> nun. long, in a terminal long-exserted 



panicle 1 10 cm. long; outermost glume of sessile spikelet 3-4 mm. long, about 



