44 PANICEAE 



II. CENCHRUS L. 



I. CenchrUS tribuloides L. Sand Bur Common in the 

 cultivated areas throuhout the State though more common at the 

 lower levels: a troublesome weed. 



12. CHAETOCHLOA Scribn. 



Panicles spike-like, dense, with numerous, 

 crowded spikelets. 

 Spikelets arranged singly in racemes;. 5-16 

 bristles at the base of each spikelet, 

 somewhat tawny. 1. C. glauca. 



Spikelets clustered, i.ot in racemes; 1-3 



bristles at the base of each spikelet, 



bright green. 2. C. viridis. 



Panicles more slender and interrupted, some- 

 times slightly spreading. 

 Leaf blades mostly more than 1-4 inch wide; 



panicles slightly branched below. 3. C. yriesebachii. 



Leaf blades less than 1-4 inch wide; panicles 



cylindric, not showing branches, a short 



lived perennial. 4. C. composita. 



1. Chaetochloa glauca (L.) Scribn. Foxtail, a common 

 field weed at several places in the State where it has been introduced 

 with garden and field crops. Probably much more common than the 

 records show. 



2. Chaetochloa viridis (L.) Scribn. foxtail. Very sunilar 

 to the last in general appearance, but greener. It is a very common 

 field weed all over the State wherever crops are grown. 



3. Chaetochloa griesbachii (Fowm.) Scribn. var. ampla 



Scribn. and Memll. A rather rare grass in the mountains of the 

 southern part of the State, in the Upper Sonoran Zone. 



4. Chaetochloa COmposita (H. B. K.) Scribn. Common on 

 the lower mesas and in the foothills in the southern half of the 

 State, in the Sonoran Zones. 



5. Chaetochloa italica (L.) Scribn. Italian Millet. 

 Hungarian Grass. Is cultivated in a few places in the eastern part 

 of the State and will probably be more cultivated as population 

 increases. It is apt to escape. It may be recognized by the much 

 thicker panicle often 1 inch in diameter, of crowded spikelets. 



