FLORA 07 THE DISTRICT OP COLUMBIA. 45
S. SOBGHASTBTJM
43. MELICA L
1. Melica mutica Walt.
Rocky woods; frequent above the fall line. Southern states, north to Pa.
4* TJNIOLA L.
Panicle contracted, slender; spikelets 5-7 mm. long, narrow 1. V. laxa.
Panicle open, the branches drooping; spikelets 1.5-3 cm. long, broad and very flat.
2. latifolia.
1. Uniola laxa (L.) B. S. P.
Moist woods; east of the fall line; infrequent. Summer. Southern states, north- ward to Long Isl. (U. gracilis Michx.)
2. Uniola latifolia Michx.
Rich woods; above the fall line. Summer. Southern states, north to Pa.
A handsome grass, the drooping panicles of large, very flat spikelets being very striking.
' 45. DACTSXIS L.
1. Daetylis glomerate L. Obchabd qbass.
Cultivated as a meadow grass; frequently established in grassland and along road- sides. May. Native of Eur.
46. FOA L. Bluegbass.
Plants annual.
Florets not cottony at base; intermediate nerves of lemma distinct 1. P. annua.
Florets with cottony hairs at base; intermediate nerves indistinct.2. P. ehapmaniana.
Plants perennial.
Creepingjrootstocks present.
Culms distinctly flattened; plants not tufted; panicles contracted,
8. F. compress*.
Culms terete or obscurely flattened; plants tufted; panicles open.
Lower branches of the panicle usually in twos; basal leaves usually as long as the culm 4. P. cuspldata.
Lower branches of the panicle usually in fives; basal leaves shorter than the culm 5. P. pratensis.
Creeping rootstocks wanting.
Lemma not cobwebby at base, conspicuously scarious at the rounded apex.
6. P.autumnalis.
Lemma cobwebby at base.
Sheaths upwardly scabrous; marginal nerves of the lemma glabrous.
7. P. triTialis.
Sheaths glabrous; marginal nerves of the lemma pubescent.
Intermediate nerves of the lemma faint; branches of the panicle ascending or spreading; lemma usually purple-tinged 8. P. palnstris.
Intermediate nerves of the lemma prominent; branches of the panicle finally re flexed; lemma green 8. P. sylvestrl*.
1. Poa annua L.
A common weed in lawns and waste places. Flowering in early spring or even in warm weather during the winter. Common throughout the warmer parts of the U. 8., and in the Old World.
2. Poa chapmaniana Scribn.
Arlington Farm (Wheeler). Open ground, southern states.
3. Poa compressa L. Canada blueorass.
Grassland and waste places, especially in sterile soil; a weed in gardens. June.
Introduced from Eur. and now distributed throughout theU. S. {Including P. com- pressa graeilis of Ward's Flora.)
4. Poa cuspidata Nutt.
Rocky woods; infrequent; mostly above the fall line. Apr. N. Y. to Ga. and 111.
(P. brachyphylla Schult,; P. brewfolia Muhl.)
Except the introduced P. annua this is the earliest of all our grasses to bloom.
6. Poa pratensis L. Kentucky bluegrass.
Common in grassland. May. Cultivated as a lawn and pasture grass in the cooler parts of the U. S. and well established; native of Eur.
6. Poa antumnalis Muhl.
Low woods; frequent. May. Southern states, north to Fa. (P. ftexuosa Muhl.) 7. Poa trivialis L. Rough-stalked meadow grass.
Moist places, ditches, and river banks; infrequent; along the Potomac above Georgetown. June. Introduced from Eur.
8. Poa palustris L.
Moist meadows; rare. July. Southern states, north to Fa.; also in Eur. and Asia.
(P. triflora Gilib.)
9. Poa sylvestris A. Gray.
Rocky woods; frequent, May. Eastern U. S.
47. PANICTJLABIA Fabr.
Spikelets terete, 1.5-2 cm. long 1. p. septentrionalis.
Spikelets ovate or oblong, usually not over 7 mm. long.
Panicle contracted, oblong 2. P. obtusa.
Panicle open, lax.
Spikelets 3-4 mm. wide; lemmas obscurely nerved.
Lemmaa about 2.5 mm. long; spikelets usually not over 5-flowered; middle nodes of panicle (nth 3-5 primary branches; panicle 3-5 times branched.
3. P. laxa.
Lemmas.a little over 3 mm. long; spikelets usually more than 5-flowered;
middle nodes of panicle with 1-3 primary branches; panicle 2-3 times branched 4. P. canadensis.
Spikelets not over 2.5 mm. wide; lemmas prominently nerved.
Glumes short and rounded, the lower about 1 mm. long; lemmas about 2 mm.
long 5, P. nemta.
Glumes oblong, the lower 1.5 2 mm. long; lemmas about 3 mm. long.
6. P. pallida.
1. Panicularia septentrionalis (tiitchr.) Bicknell,
Marshes and river banks; infrequent; Bladensburg; Broad water. June. North- ern states, south to Va. (Glyceria teptcntrionalis Ilitchc.; G. fiuitans of Ward's Flora.) 2. Panicularia obtusa (Muhl.) Kuntze.
Swales and river banks; rare; Oxon Run (Steele), Aug. Near the coast, N. Eng.
and southward. (Glyceria obtusa Trin.) 3. Panicularia laxa Scribn.
Swalea; rare; Terra Cotta Swamp (Ward); Suitland. June. Me. to Md. (Glyceria laxa Scribn.; <5. aquatica of Ward's Flora.)
FLORA. OF THE DISTRICT OF COLUMBIA 89
4. Panicularia canadensis (Michx.) Kuntze. Rattlesnake grass.
Swalee below the fall line; infrequent. Summer. Northern states, south to Md.
(Glyceria canadensis Trin.)
5. Panlcnlaxla nervata (Willd.) Kuntze.
Swales and wet places; frequent. May-June. Throughout the U. S. (Glyceria nervata Trin.)
6. Panicalaiia pallida (Torr.) Kuntze.
Swales and stream borders; rare; Bladensburg (Steele). June. Northern states, south to Va. (Glyceria pallida Trin.)
48. FESTTJCA L. Fescue grass.
Plants annual.
Glumes somewhat unequal, the lower 3 mm. long; spikelets 5-13-flowered; lemma without scarious margin; awn usually not longer than the lemma.
1, F. octoflora.
Glumes very unequal, the lower 1.5-2 mm. long; spikelets 1-5-flowered; lemma scarious-maigined; awn about twice as long as the lemma 2. F. mynros.
Plants perennial.
Blades involute; panicle short and contracted.
Culms erect, pale at base 3. P. ovina.
Culms decumbent and usually purplish at base 4. F. rabra.
Blades flat; panicle long and narrow, or open with spreading branches.
Lemmas 5-7 mm. long; panicle narrow, with short erect branches..S. F elatlor.
Lemmas about 4 mm. long; panicle very loose, with long spreading or drooping branches. ...6. F. obtasa.
1. Festuca octoflora Walt.
Open or sterile ground;'common. May-June. Throughout the U. S. (F. tmella Willd.)
2. Festuca myuros L.
Open ground; frequent. June. Eastern states; naturalized from Eur.
3. Festuca ovina L. Sheep fescue.
Pastures and grassland; infrequent. June. Introduced from Bur.; occasionally cultivated as a pasture grass.
4. Festuca rdbra L. Red fescue.
Sometimes cultivated in grass mixtures; occasionally escaped. June. Native of Eur.
fi. Festuca elatior L. Meadow fescue.
Grassland and open ground; frequent. June. Cultivated as a meadow grass;
introduced from Eur.; well established in many places.
6. Festuca obtusa Spreng.
Rocky or rich woods; frequent above the fall line. May-June. Eastern states.
(F. nutans Willd.)
49. BBOMVS L. Brome grass.
Spikelets much flattened, the lemmas keeled, the awn not more than 2 mm. long.
1. B. unioloides.
Spikelets terete or slightly flattened, the lemmas not keeled or keeled only toward the apex, the awn conspicuous (except in B. inermis).
Plants perennial.
Creeping rootstocks present; lemma glabrous, awnless or mucronate.
2. B, Inermis.
Creeping rootstocks wanting; lemma pubescent, awned.
Sheaths usually not overlapping, rather loosely pilose 3. B. purgans.
Sheaths overlapping, densely soft-pilose 3a. B. purgans lncanns.
Plants annual.
Lemmas narrow, gradually acuminate.
Second glume usually less than 1 cm. long; pedicels capillary, flexuous.
4. B. tectorum.
Second glume more than 1 cm. long; pedicels not capillary and flexuous.
Awn about 2 cm. long; first glume about 8 mm. long 5. B. sterills.
Awn 3-5 cm. long; first glume about 15 mm. long 9. B. vlllosus.
Lemmas broad, abruptly narrowed above, glabrous.
Sheathe glabrous 6. B. secalinus.
Sheaths pilose
Panicle rather dense 8. B. racemosus.
Panicle open.
Lemma smooth, the awn straight... 7. B. commutatus.
Lemma scabrous, the awn divergent 10. B. japonicus.
1. Bromus unioloides (Willd.) H. B. K. Rescue grass.
Occasionally escaped from cultivation in the vicinity of Arlington Farm. Culti- vated in the southern states as a forage grass. Originally from S. Amer.
2. Bromus inermis Ley63. Awnless beome grass.
. Occasionally escaped from the experimental plots or propagating grounds. Culti- vated in the northwestern states as a forage grass. Originally from Eur,
8. Bromus purgans L.
Rich or rocky woods; frequent,. June-July. Eastern U. S. {B. ciliatui purgans A. Gray; B. ciliatus of Ward's Flora.)
3a. Bromus purgans incanus Shear.
Rocky woods along the Potomac; infrequent. Aug. Pa. to Va. and westward.
4. Bromus tectorum L.
A weed in waste ground; infrequent. June. Introduced from Eur.
5. Bromus sterllis L.
Waste places; rare; Old Observatory (Steele); Holmead {Ward); Uniontown (Ward).
June. Introduced from Eur.
6. Bromus secalinus L. Chess.
Fields and waste ground; frequent. June. Introduced from Eur.
Also called cheat.
7. Bromus commutatus Schrad.
Waste places; frequent. June. Introduced from Eur.
8. Bromus racemosus L.
Waste places; infrequent. June. Introduced from Eur. (5. 1nollia of Ward's Flora.)
9. Bromus villosus Forsk.
Waste places; becoming frequent from College Park to Beltsville- June. Intro- duced from Eur.
10. Bromus japonicus Thunb.
Waste places; near Suitland. July. Introduced from Eur.
50. LOLITJM L. Rye grass.
1. Loilum perenne L. Perennial rye on ass.
Grassland and open ground; common. June. Cultivated as a lawn grass, especially in parks; originally from Eur.
SI. AGROPYRON Beauv. Wheat grass.
1. Agxopyron repens (L.) Beauv. Couch grass.
Open ground and grassland; frequent. June. Introduced from Eur. (Triticwn repens L.)
A troublesome weed on account of its creeping rootstocks. Also called quack, quitch, and quick grass.
FLORA OF THE DISTRICT OF COLUMBIA 91