ORDER CXLII. GKAMTNACE.E. 585 



digitate, 3 — 5 ; paleae longer than the rudiment. — An introduced grass. 

 Very difficult to exterminate, especially in loose, rich soil. 



Bermuda Grass. Digitaria dactylon, Ell. 



Genus XX.— CHLO'PJS. Schwartz. 

 (From chloros, green, in allusion to its herbage.) 



Flowers polygamous. Glumes 2, 2-flowered ; one of thetn 

 perfect and sessile, the other staminate. Paleae of the perfect 

 flower 2, awned. Spikes by fours, digitate. 



1. C. petr^'a, (Ell.) (Eustachys petraia, Desv.) Stem prostrate, 

 branching, assurgent, geniculate. Leaves glabrous, with the margins 

 and midrib serrulate. Glumes 2, 2-flowered ; exterior glume awned, 

 the interior smaller, keeled. Palea of the sterile floret concave, ob 

 tuse. — 1(. June — Aug. On the sea-coast. 



Genus XXL— ELEUSI'NE. Gaart. 

 (From Eleusin, the name of a town where Ceres was worshiped.) 



Flowers on one side of the rachis. Glumes 2, unequal, 5 — 7- 

 flowered. Palece 2, obtuse, upper one bifid. Scales fimbriate. 

 Spikes digitate. 



1. E. muorona'ta, (Mich.) {Leptochloa mucronata, Kunth.) Stem 

 erect, glabrous. Leaves slightly scabrous, with hispid sheaths longer 

 than the joints. Panicle long, with the spikes 4 — 5 inches long. Glumes 

 nearly equal, with colored keels. Palece unequal, the exterior hairy. — 

 0. July — Oct. Cultivated lands. 1 — 3 feet. 



2. E. in'dica, (Gsert.) Stem decumbent, lucid. Leaves linear, with 

 the under surface glabrous, long ; sheaths pubescent, compressed. 

 Spikes usually 5, digitate, one below the rest ; spikelets usually 5-flow- 

 ered. Glumes unequal, with the keels scabrous. — %. June — October. 

 Common. 1 — 2 feet. 



3. E. crucia'ta. {Dactyloctemum JEgyptiacum, Willd.) Stem de- 

 cumbent and assurgent, glabrous. Leaves narrow, ciliate. Spikes 2 — 

 4; spikelets usually 3-flowered, the terminal one usually sterile or 

 wanting ; extremity of the rachis naked. — ©. July. Common. 12 — 

 18 inches. 



Genus XXII.— MONOCE'RA. Ell. 

 (From rrwnos, one, and keros, horn ; there being but one spike.) 



Flowers polygamous, on one side of the rachis. Glumes 2, 

 many-flowered, awned below the summit. Palere of the per- 

 fect flower 2-valved, unequal ; the exterior one awned below 

 the summit ; those of the sterile flower unawned. 



1. M. aromat'ica, (Ell.) {Ctenium Americanum, Sprig.) Stem pu- 

 bescent, erect. leaves scabrous on the upper surface, glabrous be- 

 neath ; sheaths shorter than the joints, hairy at the throat. Spikes ter- 

 minal, secund ; spikelets in 2 rows. Glumes 3-flowered; the exterior 

 glume with an awn projecting from the center of the back ; the interior 

 palea small, pubescent. — 2£. May — July. Pine-barrens. 



Toothache-grass. 



25* 



