588 ORDER CXLII. GRAMINACE^E. 



1. U. purpu'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. — |g|. Sept. — Oct. Sea-coast. 1 — 2 feet. 



2. U. cup'rea, (Kunth.) (Poa quinqueflda, 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. 

 — U- 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 dai^k-purple, sessile. — 2£. Sept. 2 feet. 



Tribe VIII.— FESTUCIN'EJS. 



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

 generally without awns. 



Genus XXVIII.— 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. P. Michaux'ii, (Kunth.) (Uniola spicata, L.) Stem erect, terete, 

 glabrous. Leaves distichous, subulate, involute. Panicle compressed. 

 Glumes 2 — 3, 8 — 10-flowered. — U- 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. — 0. July — Aug. Sandy fields. 8 — 12 inches. 



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

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

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

 fields. 1—2 feet. 



4. P. capilla'ris, (L.) Stem erect, glabrous. Leaves linear, hairy, 

 short, flat ; sheath longer than the joints, hairy at the throat. Panicle 

 very large, expanding, capillary ; spikelets 3-fiowered, ovate. Glumes 

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

 1—2 feet. 



5. P. eragros'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 — 15 flowered ; florets ob- 

 tuse ; exterior palea acute, 5-nerved, transparent. — 0. July — Aug 

 Sandy fields. 12 — 18 inches. 



6. P. rep'tans, (Mich.) Stem decumbent, glabrous, terete, creep- 

 ing, branched. Leaves subulate, striate, slightly pubescent; sheath 

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



