POACEAE. y 



Flowering scale l-awned. 23. Aristida. 



Awn untwisted. 

 Awn twisted. 

 Flowering scale usually hj-aline or membranous at ma- 

 turity, at least more delicate than the empty ones : grain 

 loosely enclosed. 20. Sporobolus. 



Tribe V. CIILORIDEAE. 

 Spikelets deciduous as a whole. 27. Sp.vrtixa. 



Spikelets with at least the empty scales persistent. 

 Spikelets with one perfect flower. 



No scales above the (lowering scale. 28. Capriola. 



1-several scales above the flower. 



Spikes in whorls or closely approximate. 29. Edstachys. 



Spikes scattered. 



Spikelets scattered or distant. 30. Gymnopogon. 



Spikelets crowded. 31. Bouteloua. 



Spikelets with 2 or 3 perfect flowers. 



Spikes with terminal spikelets. 32. Eleusine. 



Spikes with the rachis extending beyond the spikelets 



in a manifest point. 33. Dactyloctenicm. 



Tribe VI. FESTUCEAE. 



Hairs on the rachilla or flowering scale very long, and en- 

 closing the latter: tall reed-like grasses. 34. Phragmites. 

 Hairs on the rachilla or flowering scales shorter than the 

 scale : lower grasses, not reed-like. 

 Flowering scales 1-3-nerved. 35. Er.\grostis. 

 Flowering scales 5-nerved. 



Emptv basal scales 3-6. 36. Uxiola. 



Empty basal scales 2. 37. Distichlis. 



1. TKIPSACUM L. Erect monoecious plants with stout rootstoeks. 

 Spikes articulate, elongate. Staminate spikelets 2-flowered, in pairs. Pistillate 

 spikelets 1-flowered, in excavations in the raeliis, the scales thick and shining. 

 — Gama-grass or Sesame-grass. 



Spikes in pairs, or more, terminal and axillary : leaf-blades mostly over 1..5 cm. wide, 

 auricled at the base. 1- T. duvtulutdes. 



Spikes single, terminal : leaf-blades mostly less than 1 cm. wide, 



not auricled at the base. 2. T. floridanum. 



1. T. dactyloides L. Stems 1-2.5 m. tall: leaf -blades 6 dm. long or less: 

 spikes 1-3 dm. long, the 5 or * pistillate, the upper portion staminate. — 

 Hammocks. — {Bah., Ant.) 



2. T. floridanum Porter. Similar to no. 1, but much more slender: stems 6-10 

 dm. tall: leaf -blades long and narrow: spikes rather slender, 1.5-2 dm. long. — 

 Pinelands and adjacent everglades. — F. K. 



2. IMPEEATA Cyr. Erect plants with long terminal cylindric dens'e and 

 spike-like panicles. Spikelets 1-flowered, unequally pedicellate. Scales 4, thin, 

 hyaline, awnless, the outer 2 empty, pilose. 



1. I. brasiliensis Trin. Stems tufted, 3-8 dm. tall, slender: leaf -blades 3 dm. 

 long or less, 3-8 mm. wide: panicle 6-15 cm. long, oblong: spikelets about 4 

 mm. long, the one about equalling, the other about twice as long as its pedicel. 

 — Everglades and pinelands. — {Bah., Cuba, Ant.) — Brazilian blady-grass. 



3. EEIANTHUS :Michx. Tall plants with perfect flowers in open or con- 

 tracted terminal panicles. Spikelets usually with a basal ring of long hairs, or 

 rarely naked, in pairs. Scales 4, the outer 2 indurated, the fourth scale bearing 

 an awn which is straight, spiral or contorted. 



1. E. saccharoides Michx. Stems 1.5-3.5 m. tall, the summit and nodes 

 together witli the panicle-axis and top of the otherwise glabrous sheaths 

 appressed-pubesccnt with long silky hairs: panicle 1.5-4 dm. long: spikelets 

 about 5 as long as the basal hairs and a little exceeding the internodes, the 

 awn 1.5-2.5 cm. long. — Hammocks and pinelands. — {Cuba). — Plume-grass or 

 Beard-grass. 



