TRIANDRIA. DIGiNIA. 87 



gid, often setlform, mucronate or diminishing into a mere 

 awn. Exteror valve of the corolla generally awned. 



Species. 1. E. pMlade'phiaisP Q. canadensis. These 

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

 imperfectly defined species, and very nearly allied to 

 No. 2. 4. villosus. 5. virg-hu'cus. 6. striatus. 7. curop^e^is. 

 — § II. AsPERELLA. CulixU. CorolU 2-valved. F.xterior 

 Valve larger, mucronate. — Humboldt. 9. Hystrix? Spike- 

 lets 4-flowered; involucrate calix 0, but corresponding- 

 callosities in its place. 



A genus of but ^^^^ species, existing- in Europe, Ame» 

 rica, Northern Asia (Siberia), and Northcn Africa (Bar- 

 bary). Except in North \merica where 8 ouj- ot 11 spe- 

 cies exi-.t, this genus is confined »o the sea-coast. ^ The 

 E. areyiarijis, is one of hose grasses which assist in ar- 

 resting the progress of moveable sands. 



119. HORDh:UM. L, (Bailey.) 



Culyces lateral, 2 vaiveJ, iriosily l-uowereu, 

 a£!:gr< gated by tlirccs. s;» as to resembie a seta- 

 ceous 6 leaved iuvolucrum; the central flower 

 sessile, the lateral ones stipitate, usually sterile. 

 Corolla 2-valved. acute; exterior valve awned. 



Very nearly allied both by habit and character to the 

 preceding genus. Flowers spiked, imbricated mos'lyin 

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

 approaching by pairs. In the H hexastichon, the flowers 

 are imbricated in 6 ranks, because all the flo-weis are 

 hermaphrodite; probably a mere effect of cultivation. 



Species. 1. H vu'gare. Cultivated. Flowers all her- 

 maphrodite; probably the effect of culture? Still found 

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

 masculine or neutral flowers awnless, acute; four 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, s'riate, 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 



