20 GRAMINEAE 



Spikes 3^' or less long, J' or less thick, not notice- 

 ably compound. 



Spikes yellow, very erect and closely flowered. 3. C. glauca. 



Spikes green, less closely flowered and more 



nodding. 2. G. viridis. 



1. C. verticillata (L.) Scribn. Foxtail. 1°-2° high, with a pale 

 green spike 2'-3' long : bristles one or two to each flower, slightly ex- 

 ceeding the spikelet. — Waste places in Independence. Uncommon. 



2. C. glauca (L.) Scribn. Yellow Foxtail. 1°-4° high, the 

 slightly flexnous tawny yellow spike l'-4' long : bristles 6-11 to each 

 spikelet, much longer than the spikelet : first scale shorter than the 

 second : third and fourth scales equal, longer than the second : fourth 

 scale transversely rugose. — Extremely abundant in vpaste places, corn- 

 fields, along railroads and the like. 



3. C. viridis (L.) Scribn. Gkeen Foxtail. Closely resembles the 

 last, but the green spikes are more nodding and less closely flowered, 

 and the bristles are fewer in number : the first scale one-third the length 

 of the other three, which are about equal in length : fourth scale striate 

 lengthwise and pitted. — Growing with the last and about as common. 



4. C. Italica (L.) Scribn. MilYet. 2°-5° high with a large com- 

 pound spike, 4''-8' long, 10"-15" broad, usually interrupted at base : 

 bristles 2-3 : splkelets much as in the last : heads nodding or erect. — 

 Occasionally escaped into waste lots and along railroads. 



Var. Germanloa (Mill. ) Scribn. Hungaeian Gbass. Smaller than 

 the species : spikes about 6" broad : bristles usually purplish. — In simi- 

 lar situations as the type. 



10. CENCHRUS L. 



Spikelets awnle.ss ; as in Panicum, but several are enclosed together in a 

 horridly spiny involucre. Involucres forming an interrupted terminal 

 spike. 



1. C. tribuloidea L. Bue-gkass. A decumbent annual, S'- 20' high : 

 spikes about 2' long, with 8-20 two-flowered heads ; involucres pubes- 

 cent, covered all over with short stout barbed spines. — -A troublesome 

 ■weed, often common in sandy grounds along the Missouri River. July- 

 October. 



11. ZIZANIA L. 



A tall aquatic with monoecious flowers in a terminal panicle. Upper 

 flowers pistillate and erect, long-awned, the lower staminate and droop- 

 ing, unawned. Glumes two. Stamens six. 



1. Z. aquatica L. Wild ElCE. Annual, 3°- 10° high, with long flat 

 leaves, l°-3° long : spikelets very deciduous, and early breaking from 

 the rachis. — In the lake at Lake City. Bare. July-October. 



12. HOMALOCENCHRUS Mieg. CUT-GEASS. 

 Lowland grasses with flat spikelets crowded in one-sided panicles. 

 Spikelets usually imbricated over each other. Glumes two, strongly 



