36 



CLASS III. ORDER II. 



paleas 2-valved, awiilesfi, nnequal ; flowers 

 m unilateral spikes, somewhat imbricated 

 in 2-rows. (salt-gras-s.) 



Kyllin"ga. Flowers distinct, disposed 

 in a roundish, sessile, sub-imbricated t^pike ; 

 glumes 2*valved, l-Howered; palcas 2, 

 longer than the glumes, (bog-rush.) 



Okyzop"sis. Glume 1-flowered, 2-valv- 

 ed ; valves membranaceous, nearly equal, 

 lax, oboviite, awnloss; paleas 2, coriacfeous, 

 cylindric ovate, hairy at tbe base, the low- 

 er one awncd at the tip ; scales linear-elon- 

 gated; flowers panicled. (mountain rice.) 



RhYxVCHOS "poRA. Glumes fascicled into 

 a spike, the lower ones empty; seed 1, 

 crowned with a persistent style ; bristles 

 surrounding the base, (false bog-rush.) 



Schce'nus. Glumes fascicled into a spike, 

 the lower ones empty ; style deciduous ; 

 seeds naked. 



SciK"rus. Glume 1-valved, 1-flowered, 

 imbricated on all sides ; seed or nut naked 

 or bristled at the base, (club-rush.) 



Mie'gia. Flowers polygamous, panicled ; 

 glume 2-valved, many-flowered, short and 

 unequal ; paleas 2, unequal, the larger one 

 acuminate ; style very short, 3-cleft, plu- 

 mose ; nectary 3-parted, divisions lanceo- 

 late, acute, as long as the germ, large, 

 acuminate, (cane.) S. 



Nar'^dcs. Glume 1-flowered, 1-valved ; 

 palea 1, included in the calyx ; stigma 1. 

 Flowers spiked, alternadug and sessUe. 

 (mat-grass.) 



Xy'ris. Calyx a cartilaginous glume, 2 

 or 3-valved, in a head ; corolla 4-petalled, 

 equal, crenatc ; capsule 3-valved, many- 

 seeded, (yellow-eyed grass,) 



ORDER II. DYGTNIA. 



A. Spihelets \-flowered; corollas without 



abortive mdi7nents ofjlowers at the base. 



[Calyx and corolla different in texture.] 



Leer"sia. Calyx 0; corolla 2-valved, 

 closed ; valves compressed, boat-shaped ; 

 nectary obovate, entire, collateral; sta- 

 mens varj'ing in number, (cut-grass.) 



Mil'^ium. Glume 2-valvea, naked, beai'd- 

 less ; paleas 2, oblong, concave, shorter 

 than the glume, awnless; seed 2-horned; 

 flowers panicled. (cane.) 



Pas"palu.m. Glume in 2 membranaceous, 

 equal, roundi.sh valves; paleas awnle.ss, 

 cartilaginous, of the form of the glume ; 

 Btigraa plumose, colored ; nectary lateral ; 

 flowers in unilateral spikes. 



Piptathe'rum. Glume membranaceous, 

 longer than the cartilaginous, oval paleas; 

 lower valve awned at the tip ; nectary 

 ovate, entire ; seed coated. 



Aris''tida. Glume 2-valved, membrana- 

 ceous, unequal ; paleas 2-valved, pedicel- 

 led, sub-cyhndric, lower valve coriaceous, 

 involute, 3-awned at the tip, upper valve 

 very minute or obsolete ; nectary lateral, 

 (beard-grass.) 



Sti'pa. Glume 2-valved, membranaceous ; 



f)alea3 2-valved, coriaceous, valves invo- 

 ute, truncate ; awn terminal., long, cadu- 

 cous ; seed coated, (feather-grass.) 

 Sac/'charum. Calyx involucred, with 



I long wool at the base, 2-valved ; coroUa i 

 ' or 2-valved ; stamens 1 to 3. (sugar-cane.) 



i [Cal>/x and corolla of similar texture— 

 Jloicers in spreading panicles.] 



Agros"tis. Calyx herbaceous, 2-valved, 

 1-flowered, valves acute, a little less than • 

 the corolla ; corolla 2-valved, membrana- 

 ceous, often hairy at the base ; stigmas 

 longitudinally hispid or plumose; florets 

 spreading; nectary lateral; seed coated, 

 (redtop.) 



Muhlenberg'''ia. Glumes 2, very mi- 

 nute, unequal, one scarcely perceptible, 

 paleas 2, many times longer than the 

 glumes, linear-lanceolate, nerved, hairy at 

 basc^ the lower one terminating in a long 

 awn. 



Aru\'''do. Calyx 2-valved, unequal, mem- 

 branaceous, sun-ounded Avith hair at the 

 base, lower valve mucronate or slightly 

 awncd. Sometimes there is a pencil-form 

 rudiment at the base of the upper valve, 

 (reed.) 

 [Calyx and corolla of similar texture; 



flowers in compact panicles, often spike- 

 form.] 



Phle'um. Calyx hard, 2-valved, equal, 

 sessile, linear, truncate, bicuspidato ; co- 

 rolla enclosed in the calyx, 2-valved, av^Ti- 

 less, truncate, (timothy-grass.) 



Alopecu'rus. Glumes 2, equal, gener 

 ally connate at the base ; paleas 1-valved, 

 utricle-like, cleft on one side, awned below 

 the middle, (foxtail-grass.) 



B. Spikelets 1-Jlotcered ; corolla with 1 or 

 2 abortive r^idiments of floicers at the base. 

 [Calyx and corolla of similar texture.] 

 Phala'ris. Calyx membranaceous, 2- 



valved, valves keeled, n^^-ed, equal in 

 length, including the 2-valved, pilose corol- 

 la ; the corolla is shorter than the calyx 

 and coriaceous ; rudiments opposite, ses- 

 sile, resembling valves ; nectary lateral, 

 (riband-grass, canarj'-grass.) 



C. Spikelets many -flowered. [Flowers in 



panicles ; corolla unarmed.] 



Phragmi'tes. Calyx 5 to 7-flowered; 

 the florets on villose pedicels, lower 

 valve elongated, acuminate, involute, up- 

 per one some%vhat conduplicate. 



Bri'za. Spikelets heart-ovate, many- 

 flowered ; calyx chaff"}', shorter than the 

 2-ranked florets; corolla ventricose, lower 

 valve cordate, upper one orbicular, short, 

 (quake-grass.) 



Po'a. Spikelets oblong or linear, com 

 pressed, many-flowered ; calyx shorter 

 than the florets ; corolla herbaceous, awn- 

 less, often scarious at the base ; lower 

 valve scarious at the margin, (spear-grass.) 



Sor"ghum. Florets in pairs, one perfect, 

 with a 3-valved corolla and sessile, the 

 other staminate or neutral, and pedicelled. 

 (broom-corn.) Ex. 



[Flowers in paiiicles ; corolla armed or 

 mucronate.] 



Dac^'tylis. Spikelets aggregated in 

 unilateral heads, many- flowered ; c.-ii.v'x 



