CLASS IV. ORDER I. 345 



corolla enclosed in the calyx, 2-valved, awnless, truncate. 4. 10 (timothy- 

 grass). S. 

 B. Spikelets 1 flowered ; corolla with 1 or 2 abortive rudiments of flowers at th* 



base. 



(Calyx and corolla of similar texture). 



PHALA'RIS. Calyx membranaceous, 2-valved, valves keeled, nerved, equal 

 in length, including the 2-valyed pilose corolla. The corolla is shorter than 

 the calyx and coriaceous : rudiments opposite, sessile, resembling valves : nec- 

 tary lateral. 4. 10 (ribbon-grass, canary-grass). -S. 

 C. Spikelets many-flowered. 

 (Flowers in panicles ; corolla unarmed). 



BRI'ZA. Spikelets heart-ovate, many-flowered : calyx chaffy, shorter than 

 the 2-ranked florets : corolla ventricose : lower valve cordate, upper one orbi- 

 cular, short. 4. 10 (quake-grass). S. 



PO'A. Spikelets oblong or linear, compressed, many-flowered : calyx short- 

 er than the florets : corolla herbaceous, awnless, often arachnoid at the base ; 

 lower valve scarious at the margin. 4. 10. (spear-grass). S. 



Exotic. 



SORG"HUM. Florets in pairs, one perfect, with a 3-valved corolla, and ses- 

 sile ; the other staminate or neutral, and pedicelled. 4. 10 (broom-corn). 



(Flowers in panicles ; corol armed t or mucronate.) 



DAC"TYLIS. Spikelets aggregated in unilateral heads, many-flowered : ca- 

 lyx shorter than the florets, with one large glume, keeled, pointed . corolla 

 with the lower valve keeled, emarginate, mucronate ; upper valve sub-condu- 

 plicate. 4. 10 (orchard-grass.) S. 



AVE'NA. Calyx 2-valved ; 2, 3, or many flowered : corolla, valves mostly 

 bearded at the base, lower one torn, with a twisted awn on the back : glumes 

 membranaceous, and somewhat follicle-like : seed coated. 4. 10 (oats). S. 



D. Flowers in spikes. 



LO'LIUM. Calyx 1 -leafed, permanent, many flowered ; florets in many flow- 

 ered 2-rowed simple sessile spikelets on a rachis : lower valve of the corolla 

 herbaceous-membranaceous, mucronate, or bristled at the tip. 4. 10 (darnel- 

 grass.) 



TRI'TICUM. Calyx 2-valved, about 3-flowered ; florets sessile on the teeth 

 of the rachis, obtusish and pointed ; glumes beardless, or interruptedly bearded. 

 4. 10. (wheat). 



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 varre long-awned. 

 4. lO-(rye). 



E. Flowers polygamous. 



(in panicles'). 



PAN"ICUM. Calyx 2-valved, 2-flowered ; the lower glume generally very 

 small ; the lower floret abortive, 1 or 2-valved ; the lower valve resembling 

 the calyx, the upper one membranaceous : perfect floret with cartilaginous 

 valves, unarmed. 4. 10 (cockfoot-grass, panic-grass). -S. 



(In spikes). 



HOR"DEUM. Spikelets 3 at each joint of the rachis, 1 or 2-flowered, all per- 

 fect, or the lateral ones abortive : glume lateral, subulate : perfect flower with 

 a 2-valved corolla ; lower valve ending in a bristle : seed coated. 4. 10 

 (barley). 



ORDER III. TRIGYNJA. 



MOLLU'GO. Calyx 5-leaved, coloured within : corol : capsule 3-celled, 3- 

 valred. 22. 82 (carpet-weed). S. 



CLASS IV. TETRANDRIA. 



ORDER I. MONOGYNIA. 

 A. Flowers superior. 



(1-petalled). 



CEPHALAN"THUS. Inflorescence in a head : general calyx none ; proper ca- 

 lyx superior, minute, angular, 4-cleft : corolla funnel-form ; receptacle globu- 

 lar, hairy: capsules 2 to 4-partible : seed solitary, oblong. 48. 56 (buttou- 

 bush). S. 



