POACEAE: PANICEAE 39 
1. Phalaris arundinacea L. Reed Canary-grass. 
In moist places, most abundant in the eastern part of state. Ash- 
land; Bassett; Lincoln; Plainview; Talmage; Whitman, 
2. Phalaris canariensis L. Canary-grass. 
Introduced, not common. Alliance; Lincoln; Minden; Valentine. 
Tribe 6. Paniceae, 
Spikelets without an involucre. 
Spikelets not in one-sided spikes. 1, Panicum. 
Spikelets in one-sided spikes. 
Empty scales awned or awn-pointed. 2. Echinochloa. 
Empty scales not awned. 
Spikelets not much longer than wide. 3. Paspalum. 
Spikelets about twice as long as wide. 4, Syntherisma. 
Spikelets with an involucre, i. e. accompanied by bristles or enclosed 
in a spiny burr. 
Involucre of bristles. 5. Chaetochloa. 
Involucre of valves forming a spiny bur. 6. Cenchrus. 
1. Panicum. 78, 
Plants annual. 
First empty scale not over % the length of the spikelet, truncate or 
triangular tipped. 1. P. dichotomiflorum. 
First empty scale at least 144 the length of the spikelet, acute or 
acuminate. 
Panicle narrow, usually less than half as broad as long. 
2. P. flexile. 
Panicle as broad as long. ? 
Spikelets usually less than 2.5 mm, long. 3. P. capillare. 
Spikelets usually over 2.5 mm, long. 4. P. barbipulvinatum. 
Plants perennial, 
Basal leaves similar to those of the culm; not forming a winter 
rosette; first empty scale % as long as spikelet. 5, P. virgatum. 
Basal leaves usually distinctly different from those of the culm, 
forming a winter rosette; first empty scale not more than 4% 
the length of the spikelet. 
Blades elongated, not over 5 mm. wide, 20 times as long as wide; 
autumnal form branching from base only. 
Spikelets usually over 3.2 mm. long, pointed. 6, P. depauperatum. 
Spikelets usually less than 3.2 mm. long, blunt. 
Spikelets from 2.7 to 3.2 mm. long. 7. P. perlongum. 
Spikelets from 2.2 to 2.7 mm. long. 8. P. linearifolium. 
Blades not elongated, (or if so over 5 mm, wide and autumnal 
form not branched from the base.) 
Spikelets neither turgid, blunt nor strongly nerved, 
Ligule of conspicuous hairs, usually 3-5 mm. long. 
Culms variously pubescent, if pilose the hairs not long and 
horizontally spreading. 
Autumnal form erect or leaning, never forming a mat. 
Spikelets 1.5 mm. or less long. 9. P. implicatum. 
Spikelets 1.6 mm. or more long. 
