MANUAL OF THE GRASSES OP THE UNITED STATES 



325 



The rachilla is regularly prolonged in a few species and in 

 occasional spikelets of other species. 



Most of the species are important forage 

 plants, either under cultivation or in the 

 mountain meadows of the Western States. 

 The three important cultivated species are 

 redtop, Agrostis alba, used for meadows, 

 pastures, lawns, and sports turf, Colonial bent, 

 A. tenuis, used for pastures, lawns, and sports 

 turf, and creeping bent, A. palustris, used 

 for lawns and golf greens. Velvet bent, A. canina, is sometimes 



FIGURE 651. Distribution of 

 Calamovilfa gigantea. 



FIGURE 650. Calamovilfa gigantea. Panicle, X 1 A; glumes and floret, X 5. (White, Okla.) 



used for putting greens. Recently forms of A. palustris called 

 Washington bent and Metropolitan bent, 

 have come into use for lawns and especially 

 for golf greens. They are propagated by the 

 stolons. Fiorin is a name applied in England 

 to A. palustris. 



The native species abundant enough to be 

 of importance as forage plants are A. exarata, 

 throughout the western half of the United 

 States, A. oregonensis in Oregon, and A. 

 rossae in alpine regions of the Northwest, 

 la. Palea evident, 2-nerved, at least half as long as the lemma. 

 2a. Rachilla prolonged behind the palea as a minute bristle. 



Lemma pubescent 1. A. EETROFRACTA. 



Lemma glabrous. 



Lemma awned; plants annual. 



Panicle open, the branches naked below 2. A. SPICA-VENTI. 



Panicle narrow, contracted, interrupted, the branches, or some of them 



florif erous from the base 3. A. INTERRXTPTA. 



Lemma awnless; plants perennial. 



Spikelets 2 mm long 4. A. THURBERIANA. 



Spikelets 3 mm long 5. A. AEQUIVALVIS. 



2b. Rachilla not prolonged. 



Glumes scabrous on the keel and on the back; panicle contracted, lobed, 



the short branches densely verticillate 6. A. VERTICILLATA. 



Glumes scabrous on the keel only; panicle open or, if contracted, not lobed 

 nor with densely verticillate branches. 



Plants tufted; dwarf alpine species 12. A. HUMILIS. 



Plants with rhizomes or stolons; taller species of low and medium altitudes. 



Branches of panicle naked at base, the panicle open and delicate; 



ligule as much as 2 mm long on culm leaves, less than 1 mm on 



the innovations 11. A. TENUIS. 



Branches of panicle or some of them florif erous from base; ligule as 



much as 6 mm long. 



Panicle contracted, the branches appressed; long stolons developed 

 in isolated plants. Culms decumbent at base_ 8. A. PALUSTRIS. 



