GENERA. OF GRASSES OF THE UNITED STATES. 



67 



Type species: Dactylis ylomerata L. 



Dactylis L., Sp. PI. 71, 1753 ; Gen. PL, ed. 5, 32. 1754. Linnaeus describes two 

 species, D. cynosuroides from Virginia, and D. glomerata from Europe. The 

 latter species being described in his flora 

 of Sweden is chosen as the type. 



Dactylis glomerata, orchard grass 

 (PL VIII; fig. 28), is a well-known 

 meadow and pasture grass, cultivated 

 in the humid region of the United 

 States. It is a rather coarse, erect, 

 perennial bunch-grass, soon forming 

 large tussocks, with culms 2 to 1 

 feet tall, flat blades as much as one- 

 third of an inch wide, panicles 3 to 8 

 inches long, with a few stiff branches, 

 spreading in flower, appressed in 

 fruit. In England this is called 

 cocksfoot grass. Orchard grass is 

 recommended for shaded situations, 

 as it withstands shade better than our 

 other meadow grasses. 



22. CYNOSURUS L. 



Spikelets of two kinds, sterile and 

 fertile together, the fertile sessile, 

 nearly covered by the short-pediceled 

 sterile one, these pairs imbricate in a 

 dense one-sided spikelike panicle; 

 sterile spikelets consisting of two 

 glumes and several narrow, acumi- 

 nate, 1-nerved lemmas on a continu- 

 ous rachilla; fertile spikelets 2 or 3 

 flowered, the glumes narrow, the 

 lemmas broader, rounded on the back, 

 awn-tipped, the rachilla disarticulat- 

 ing above the glumes. 



Species four, in the Mediterranean 

 region ; one occasionally cultivated in 

 the United States and sparingly es- 

 caped into waste places. 



Type species : Cynosurus cristatus L. 



Cynosurus L., Sp. PI. 72, 1753; Gen. PI., 

 ed. 5, 33. 1754. Linnaeus describes nine 

 species. The first species, C. cristatus, is 

 chosen as the type because it is an eco- 

 nomic species and is one of three species 

 described in his flora of Sweden. Of 

 the remaining Linnsean species, one, C. echinatus, is now retained in Cyno- 

 surus; (7. lima is referred to Wangenheimia ; C. durus, to Scleropoa ; C. coeru- 

 leus, to Sesleria; C. aegyptius, to Dactyloctenium ; C. indicus, to Eleusine; O. 

 paniceus, to Polypogon ; C. aureus, to Achyrodes. 



FIG. 29. Crested dog's-tail grass, 

 Cynosurus cristatus. Plant, X i ; 

 fertile spikelet and floret, X 5. 



