TRIANDRIA. DIGYNIA. $7 



gid, often setlform, mucronate or diminishing into a mere 

 awn. Exteror valve of the corolla generally avvned. 



Species. 1. E. ph-JadelpJdcics? 2. canadensis. These 

 2 are probably the same species. 3. glaucifoUus. A very 

 imperfectly defined species, and \ery nearly allied to 

 No. 2. 4 villosiis. 5. virghiicus. 6. striatiis. 7. europceus. 

 — § II. AsPERELLA. CalixO. Corolla 2-valved. Exterior 

 valve larger, mucronate. — Humboldt. 9. Hi/strix? Spike- 

 lets 4-flo\vered; involucrate calix 0, but corresponding 

 callosities in its place. 



4. genus of but few species, existing in Europe, Ame- 

 rtca, Northern Asia (Siberia), and Northein Africa (Bar- 

 bar)'). Except in North America, where 8 out of 11 spe- 

 cies exist, this genus is confined 10 the sea-coast. ^ The 

 £. arenarius, is one of ■ hose grasses which assist in ar- 

 resting the progress of moveable sands. 



119. HORDEUM. L, (Barley.) 



Calyces lateral, £-valved, mostly 1 -flowered, 

 aggn gated by threes, so as to resemble a seta- 

 ceous 6 leaved involucriim; the central flower 

 sessile, the lateral ones stipitate, usually sterile. 

 Corolla 2-valved, acute; exterior valve awned. 

 Very r.early allied both by habit and character to the 

 preceding genus. Flowers spiked, imbricated mostly in 

 2 rows; calycme involucrum setaceous, 6-leaved, divisions 

 approaching by pairs. In the H. hexastichorij the flowers 

 are imbricated in 6 ranks, because all the flowers are 

 hermaphrodite; probably a mere eftect of cultivation. 



Species. 1. ^ ■yziZ^vire. Cultivated. Flowers all her- 

 niaphi'odite; probably the effect of culture? Still found 

 wild about Margamen in Sicily. 2. *pusillum. Lateral 

 masculine or neutral flowers awnless, acute; tour internal 

 calicine glumes, coriaceous and dilated, those of the her- 

 maphrodite sublanceolate; internal valve of the lateral 

 masculine flower, subsemi-ovate. 



Culm 4 to 6 inches, decumbent, or somewhat geniculate 

 at the base. Leaves rather glaucous, a little pubescent on 

 the under surface, striate, about one and a half inches 

 long, and almost obtuse; uppermost sheath tumid and 

 very smooth, embracing the spike. Spike linear; about 

 one and a half inches long. Glumes by threes, dis- 

 tichally imbricated. Lateral imperfect flowers awnless, 

 acute; central sessile flower awned, the awn almost ex- 

 actly the length of that of the subtending calix; awns 



