586 ORDER CXLn. GRAMINACE2E. 



Genus XXIIL— SPARTI'NA. 

 (From spartine, 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. — 2f . 

 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. 

 — If. 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 palea3 ciliate on the keels. — If. August — Sept. On the sea-coast. 

 2—4 feet. 



Genus XXIV.— GYMNOPO'GOR 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. — If. Sept. — Oct. Dry soils. 1 — 2 feet. 



Tribe VII.— AVENA'CEJE. 



Spikelets 2 — many-rlowered, 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-fiowered. Palece 2, equal, inclosing* the 

 seed, exterior one usually awned. Panicle compound. 



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

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

 equal. Paleai equal, the exterior one pubescent at the base, bearing 

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



2. A. capilla'cea, (L.) Stem erect, sma!l. Leaves short, glabrous, 

 narrow. Flowers in capillary panicles, diffuse, large for the size of the 

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

 than the glumes. — %. July — Aug. Sandy soils. 8 — 10 inches. 



3. A. triflo'ra, (Ell.) (Graphephorum Mliottii, Kunth.) Stem erect> 

 glabrous, slender. Leaves short, flat, scabrous on the under surface 



