588 ORDER CXLII. GRAMINACE.E. 



1. U. ruRru'REA, (Kunth.) {Aira purpurea, Walt.) Stem slender, 

 compressed, scabrous at the joints. Leaves scabrous, pubescent on the 

 upper surface ; sheaths scabrous, the throat pubescent. Glumes 2- 

 flowered ; the exterior valves small, with the margins incised. Palea: 

 2, the exterior one bifid, with the midrib extending into an awn ; the 

 interior valve villous. — 0. Sept. — Oct. Sea-coast. 1 — 2 feet. 



2. U. cup'rea, (Kunth.) {Poa quinquefida, Pursh.) Stem erect, gla- 

 brous. Leaves distichous at the base, slightly serrulate ; sheath hairy 

 at the throat. Panicle expanding ; spikelets 5-flowered; exterior pa- 

 lea 3 — 5-nerved, which extends beyond the margin, hairy at the base. 

 — If. Sept. — Oct. Sandy soils. Common. 4 feet. 



3. U. ambig'ua, (Kunth.) {Poa ambigua, Ell.) Stem erect, glabrous. 

 Leaves linear, glabrous ; sheaths bearded at the throat. Panicle ex- 

 panding; spikelets dark-purple, sessile. — U- Sept. 2 feet. 



Tribe VIII.— FESTUCIN'E^E. 



Spikelets 2 — many-flowered, panicled, sometimes racemose, 

 generally without awns. 



Genus XX VIII. — PO' A. L. {Meadow-grass.) 

 (A Greek name for grass.) 



Glumes 2, usually many-flowered. Spikelets compressed. 

 PalecE sometimes woolly at the base. Scales smooth. Panicle 

 more or less branching, or scattered. 



§ 1. Spikelets 2 — many -flowered, compressed, paniculate or racemose. 



1. R Michaux'ii, (Kunth.) (Uniola spicata, L.) Stem erect, terete, 

 glabrous. L,eaves distichous, subulate, involute. Panicle compressed. 

 Glumes 2 — 3, 8 — 10 flowered. — 2f. July — Sept. On the sea-coast. 

 1 foot, 



2. P. pectina'cea, (Mich.) Stem erect or oblique. Leaves erect, 

 hairy at the base ; sheaths hairy at the throat. Panicle capillary, ex- 

 panding, pyramidal, hairy in the axils; spikelets 5 — 10-flowered; inte- 

 rior palea persistent. — &. July — Aug. Sandy fields. 8 — 12 inches. 



3. P. hirsu'ta, (Mich.) Stem erect, compressed, glabrous, branching, 

 hairy at the axils. Zeaws glabrous, long, pubescent at the base; sheath 

 hairy. Glumes glabrous, tinged with purple. — If. Aug. — Oct. Dry 

 fields. 1—2 feet. 



4. P. cumi.t.a'kis, (L.) Stem erect, glabrous. Leaves linear, hairy, 

 Bbort, flat ; sheath Longer than the joints, hairy at the throat. Panicle 

 very large, expanding, capillary; spikelets 3 flowered, ovate. Glumes 

 pubescent Palea pubescent — 0. August — Sept. Sandy fields. 

 1— -J feet. 



6 P. BBAQROs'tis, L) Stem geniculate and branching at the base, 

 glabrous. Leaves short, linear, glabrous, nerved. Panicle spreading, 

 lower branches hairy in the axils ; spikelets 9 — 1 5-flowered; florets ob- 

 tuse ; ext< rior palea acute, 5-nerved, transparent. — r). July — Aug. 

 Sandy fields. 12 — 18 inches. 



6. P. kkp'tans, (Mich.) 8tem decumbent, glabrous, terete, creep- 

 ing, branched. Leaves Bubulate, striate. Blightly pubescent; sheath 

 hairy at the throat. Panicle fascicled; .-pikelets 12 — 20-flowered ; ex- 



