CLASS III. ORDER 11. 
ORDER II. DYGYNIA. 
A. Spikelets l-Jlowered; corollas without abortive rudiments of jlowers at the 
base. [Calyx and corolla different in texture.'] 
Leer^'su. Calyx 0; corolla 2- valved, closed; valves compressed, boat-shap- 
ed; nectary obovate, entire, collateral; stamens varying in number, (cut- 
grass.) 
Sac^'charum. Calyx involucred with long wool at the base, 2-valved ; corolla 
I or 2 valved; stamens 1 to 3. (sugar-cane.) 
[ Calyx and corolla of similar texture— fioxmrs in spreading panicles ] 
Agros'^tis. Calyx herbaceous, 2-valved, 1-flowered, valves acute ; a little 
less than the corolla; corolla 2-valved, membranaceous, often hairy at the base ; 
stigmas longitudinally hispid or plumose, florets spreading; nectary lateral; 
seed coated, (redtop.) 
Arun^'do. Calyx 2-valved, unequal, membranaceous, surrounded with hair 
at the base ; lower valve mucronate or slightly awned. 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, trun cafe, picuspidatej 
corolla enclosed in the calyx, 2-valved, awnless, truncate, (timothy-grass.) 
B. Spikelets 1-flowered ; corolla tvith 1 or 2 abortive rudiments of flowers at the 
base. [Calyx and corolla of similar texture.] 
Phala'ris. Calyx membranaceous, 2-valved, valves keeled, nerved, equal in 
length, including the 2-valved pilose corolla. The corolla is shorter than the 
calyx and coriaceous; rudiments opposite, sessile, resembling valves — nectary 
lateral, (riband-grass, canary-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; upper one somewhat conduplicate. 
Bri'za. Spikelets heart-ovate, many-flowered ; calyx chaffy, shorter than the 
2-ranked florets; corolla ventricose ; lower valve cordate; upper one orbicular, 
short, (quake-grass.) 
Po'a. Spikelets oblong or linear, compressed, many-flowered ; calyx shorter 
than the florets; corolla herbaceous, awnless, often scarious at the base; lower 
valve various at the margin, (spear-grass.) 
Sorg'^'hum. Florets in pairs, one perfect, with a 3- valved corolla, and sessile; 
the other staminate or neutral, and pedicelled. (broom-corn.) Ex. 
[Flowers in panicles ; corolla armed or mucronate.] 
Dac'^tylis. Spikelets aggregated in unilateral heads, many-flowered ; calyx 
shorter than the florets, with one large glume, keeled, pointed ; corolla with the 
lower valve keeled, emarginate, mucronate ; upper valve sub-conduplicate. 
(orchard-grass.) 
Ave'na. Calyx 2-valved ; 2, 3, or many-flowered ; corolla with valves mostly 
bearded at the base, lower one torn, with a twisted awn on the back ; glumes 
membranaceous, and somewhat follicle-like ; seed coated, (oats.) Ex. 
[Flowers in spikes.] 
Lo'lium. Calyx 1-leafed, permanent, many-flowered ; florets in many flower- 
ed, 2-rowed, simple, sessile spikelets on a rachis ; lower valve of the corolla 
herbaceous-membranaceous, mucronate, or bristled at the tip. (darnel-grass.) . 
Trit'igum. Calyx 2-valved, about 3-flowered ; florets sessile on the teeth of 
the rachis, obtusish and pointed;- glumes beardless, or interruptedly bearded, 
(wheat.) Ex. 
Seca'le. Calyx 2-valved, 2 or 3-flowered; spikelets sessile on the teeth of the 
rachis, with the terminal floret abortive; calyx 2-valved; glumes subulate, 
opposite, shorter than the florets ; corolla with the lower valve long-awned. 
(rye.) Ex. 
D. Flowers polygamous. [In panicles. ] 
Pan'^icum. Calyx 2-valved, 2-flowered; the lower glume generally very 
small J theiower floret abortive, 1 or 2-valved; the lower valve resembling 
