HOW TO KNOW THE GRASSES 



24a. Spikes 3 — 7 per culm, each 1 — 2 cm. long; keels oi glumes without 



long hairs; shallow-rooted annual plants with soft bases. Fig. 270. 



SIX-WEEKS GRAMA Bouteloua barbata Lag. 



Annual; culms 10 — 30 cm. long, in 

 small tufts, erect or more commonly- 

 spreading out and forming flat mats. 

 The seeds germinate after rains, and 

 the plants mature and die rapidly, hence 

 the name "six-weeks grama." The six- 

 weeks grasses, belonging to a nimiber 

 of genera, furnish short-season feed af- 

 ter heavy rains, but their total forage 

 production is small and they are highly 

 undependable as forage plants. Dry 

 plains, especially on overgrazed pas- 

 tures. July — October. 



Figure 270 



24b. Spikes 1 — 3 per culm, each 2.5 — 5 cm. long; keels of second 

 glumes bearing scattered long hairs; perennial, with hard bases. 

 Fig. 271. 



BLUE GRAMA Bouteloua gracais (H. B. K.) Lag. 



Perennial; tufted; culms 20 — 100 cm. tall; 

 most of the curly leaves are at the base 

 of the plant. Blue grama is an excellent 

 forage grass on the Great Plains and in 

 the western mountains, furnishing good 

 feed both summer and winter. Open 

 plains, open or lightly timbered moun- 

 tainsides. It may be confused with buf- 

 falo grass (Fig. 247), with which it often 

 grows, but blue grama lacks the creep>- 

 ing stolons of buffalo grass. June — Oc- 

 tober. 



Figure 271 



143 



