CLASS IV. ORDER I. 39 



Hordeuni. Calyx lateral, 2-valved, 1 or 2-flowered ; 

 florets in threes, the middle one sessile, lateral ones often 

 barren : corol 2-valved, acute, outer valve avvned. 



PMeum. Calyx hard, 2-valved, sessile, linear, trun- 

 cate, bicuspid ate : corol inclosed. 



B. Glumes 2-flowered or more ; spiked. 



Secale. Calyx 2-valved, 2 or many flowered, opposite, 

 solitary: glumes linear-lanceolate, smooth or channelled 

 both sides. 



Tnticum. Calyx 2-valved, about 3-flowered, alter- 

 iiate ; florets obtusish and pointed : glumes beardless or 

 interruptedly bearded : spikelcts shortish. 



C. Glumes Q-Jtotvered or more ; in panicles. 



Briza. Calyx 2-valved, many flowered : spikelets ol* 

 the panicle 2-ranked : valvelets inflated, heart-form, ob- 

 tuse ; inner one minute. 



Dactylis. Calyx 2-valved, one valve smaller : coroi 

 2-valved : awnless, compressed, carinate : style long : 

 panicles strait : spikelets imbricate with lateral florets. 



Poa Calyx 2-valved, many flowered : corol ovate ; 

 valves 2-coloured, acutish, scarious at their margins : 

 spikelets of the panicle ovate, awnless. , 



Bromus. Calyx 2-valved ; spikelets oblong, terete-2- 

 ranked ; valves awned below the tip, 



Jlvena. Calyx 2-valved, many flowered ; valves with 

 a twisted awn on the back : glumes membranaceous and 

 somewhat follicle-like. 



* Alsine. 



ORDER III. TRIGYNIA. 



Mollngo. Calyx 5-leaved, inferior : corol o : capsule 

 3-cellcd, S-vahed, many seeded. 



Proserpinaca. Calyx 3-parted, superior : nut 3-sided, 

 S -eel led, crowned by the calyx. 



* Alsine. 



CLASS IV. TETRANDRIA. 

 ORDER I. MONOGYNIA. 



A. Flowers l-petalled, inferior, calyx 4-dcft. 



Plantago Corol 4-cleft reflexed : capsule 2-celled, 

 opening transversely : stamens very long. 



