586 ORDER CXLII. GRAMINACE^. 



Genus XXIIL— SPARTI'NA. 



(From spartino, a cord, from the toughness of the leaves.) 



Flowers in 1 -sided spikes, imbricate, in 2 rows. Glumes 2, 

 unequal, keeled. Palece 2, unequal, without awns. 



1. S. jun'cea, ( Willd.) Stem glabrous, columnar. Leaves linear, con- 

 volute when old ; sheaths glabrous, ciliate at the throat ; spikes few, 

 pedunculate ; exterior glume small, the interior one long, keeled ; ex- 

 terior palea shortest, the interior compressed, as long as the glume. — U. 

 Through the summer. Sea-coast. 2 — 3 feet. 



2. S. polysta'chya. Stem glabrous, columnar. Leaves broad, very- 

 long, scabrous on the upper surface ; sheath longer than the joints, 

 with the throat hairy ; spikes numerous, 10 — 12, expanding, alternate. 

 — 2/. . Sept. On the sea-coast. 3 — 10 feet. 



3. S. gla'bra, (Muhl.) (S. laevigata, Link.) Stem glabrous, fistular. 

 Leaves long, glabrous, concave ; spikes erect, appressed, 5 — 8. Glumes 

 and paleae ciliate on the keels. — U. August— Sept. On the sea-coast. 

 2—4 feet. 



Genus XXIV.— GYMNOPO'GOX. Beauv. 



(From gumnos, naked, and pogon, a beard.) 



Glumes 2, carinate, nearly equal, longer than the floret. 

 Palece shorter than the glumes, equal ; the exterior one 3- 

 nerved, terminated by a straight awn. Spike panicled. 



1. G. racemo'sus, (Beauv.) Stem erect and decumbent, glabrous, 

 short joints. Leaves distichous, cordate, lanceolate, nerved, short, gla- 

 brous ; sheaths hairy at the throat. Panicle terminal, expanding, some- 

 what verticillate. — 2f.. Sept. — Oct. Dry soils. 1 — 2 feet. 



Tribe VII.— AVENA'CE^E. 



Spikelets 2 — many-flowered, panicled ; the lower palea bear- 

 ing a twisted or bent awn on the back. 



Genus XXV— AI'RA. L. {Hair-grass.) 

 (An ancient Greek name for Darnel.) 



Glumes 2, 2 — 3-flowered. Palece 2, equal, inclosing the 

 seed, exterior one usually awned. Panicle compound. 



1. A. flkxuo'sa, (L.) Stem erect, terete, glabrous. Leaves setaceous. 

 Panicle diffuse, with the branches somewhat verticillate. Glumes un- 

 equal. Palea: equal, the exterior one pubescent at the base, bearing 

 an awn at the base. — It. August — Sept. Shady woods. 1 — 2 feet. 



2. A. capilla'cea, (L.) Stnn erect, small. leaves short, glabrous, 

 narrow. Flowers in capillary panicles, diffuse, lar^e for the size of the 

 plant Glumes acute, with the keel rough. Palccr unawned, larger 

 than tin' frluiiies. — ©. July — Aug. Sandy soils. 8 — 10 inches. 



3. A. triflo'ra, (Ell.) [Otaphephcrum K/li<>ftii % Kimth.) Stem erect, 

 glabrous, slender. Leaves short, Hat, scabious on the under surface 



