[*][*][*] Glume 3-nerved, the nerves (at least the mid-nerve) excurrent; spikelets few, in the axils of floral leaves.

54. Munroa. Low or prostrate much-branched annual.

[*][*][*][*] Glume 3- (rarely 1-) nerved, obtuse or acute, awnless; rhachis and flower naked.

55. Kleria. Panicle contracted. Spikelets 2--4-flowered. Glumes compressed-keeled, acute or mucronate.

56. Eatonia. Panicle slender, more or less dense. Spikelets 2-flowered.

Glumes very dissimilar, usually obtuse, the upper empty one enclosing the flowers.

57. Eragrostis. Spikelets flattened, 2--many-flowered. Glumes acute or acutish. Palet persistent.

[*][*][*][*][*] Glume 3--5-nerved, obtuse or abrupt-cuspidate; spikelet 3--5-flowered; upper sterile flowers convolute around each other.

58. Melica. Glumes 5-nerved or more, scarious, obtuse. Panicle simple or nearly so.

59. Diarrhena. Glumes 3-nerved, coriaceous, the flowering one abruptly cuspidate. Panicle loosely few-flowered.

[*][*][*][*][*][*] Flowering glume 5-nerved or more (sometimes obscurely so). Only the terminal flower abortive, or none.

[+] Glumes more or less strongly compressed and carinate (ventricose in n. 63).

60. Uniola. Spikelets broad, flat and 2-edged, in usually loose panicles. Glumes coriaceous, acute, the 3--6 lower ones empty.

61. Distichlis. Dicious. Spikelets large, flattened, in a close panicle. Empty glumes 2, acute.

62. Dactylis. Panicle contracted in 1-sided cl.u.s.ters. Glumes herbaceous, awn-pointed, rough-ciliate on the keel.

63. Briza. Spikelets heart-shaped, in lax panicles. Glumes roundish, ventricose, scarious-margined.

64. Poa. Spikelets small, flattened, ovate to lance-ovate, in a loose panicle. Flowering glumes membranous and scarious-margined, pointless, usually webby or p.u.b.escent toward the base.

65. Graphephorum. Spikelets compressed, in a loose panicle, the hairy jointed rhachis produced into a hairy pedicel. Glumes thin-membranous, faintly nerved, entire.

[+][+] Glumes convex on the back, not carinate (or somewhat so in n. 70).

66. Scolochloa. Spikelets subterete, in a lax panicle, the rhachis villous at the base of the flowers, ending in a naked pedicel. Glumes coriaceous, prominently 7-nerved, toothed at the apex. In water.

67. Glyceria. Spikelets terete or flattish. Flowering glumes scarious at the usually blunt summit, prominently 5--7-nerved.

68. Puccinellia. Mainly as Glyceria, but the glumes obsoletely 5-nerved.

69. Festuca. Spikelets terete or flattish. Flowering glume acute, pointed or awned at the tip, few-nerved. Styles terminal.

70. Bromus. Glume rounded or keeled on the back, mostly awned below the 2-cleft tip, 5--9-nerved. Styles scarcely terminal.

Tribe X. HORDEae. Spikelets 1--several-flowered, sessile on opposite sides of a zigzag jointed channelled rhachis, forming a spike. Empty glumes sometimes abortive or wanting. Uppermost flower imperfect or abortive.

[*] Spikelets single at each joint of the solitary spike.

71. Lolium. Spikelets many-flowered, placed edgewise on the rhachis of the spike, with one empty glume.

72. Agropyrum. Spikelets 3--several-flowered, placed flatwise on the rhachis. Empty glumes 2, right and left.

73. Lepturus. Spikelets small, 1--2-flowered; empty glumes 1 or 2. Spike very slender.

[*][*] Spikelets 2 or more at each joint of the solitary spike; the empty glumes side by side in front of the spikelets (none or rudimentary in n. 76.)

74. Hordeum. Spikelets 1-flowered, 3 at each joint, the lateral ones usually sterile.

75. Elymus. Spikelets 1--several-flowered, all perfect and similar.

76. Asprella. Spikelets few-flowered, somewhat pedicelled, 1--3 at each joint. Glumes none or small and deciduous.

Tribe XI. BAMBUSEae. Tall woody reeds, the flat leaves with a short petiole jointed upon the sheath. Spikelets few--many-flowered, flattened, in panicles or racemes.

77. Arundinaria. Flowering glumes rounded on the back, many-nerved, ac.u.minate or bristle-pointed; empty glumes very small.

1. SPARTNA, Schreber. CORD or MARSH GRa.s.s. (Pl. 9.)

Spikelets 1-flowered, very much flattened laterally, jointed and sessile in 2 ranks on the outer side of a triangular rhachis. Glumes 3, unequal, lanceolate, strongly compressed-keeled, acute or bristle-pointed, mostly rough-bristly on the keel; palet thin, equalling or longer than the flowering glume. Stamens 3. Styles long, more or less united.--Perennials, with simple and rigid often reed-like culms, from extensively creeping scaly rootstocks, racemed spikes, very smooth sheaths, and long tough leaves (whence the name, from spa?t???, _a cord_, such as was made from the bark of the _Spartium_ or Broom).

[*] _Spikelets compactly imbricated, very rough-hispid on the keels; spikes (2--4' long) more or less peduncled; culm and elongated leaves rigid._

1. S. cynosurodes, Willd. (FRESH-WATER CORD-GRa.s.s.) _Culm rather slender_ (2--6 high); _leaves narrow_ (2--4 long, ' wide below or less), tapering to a very slender point, keeled, flat, but quickly involute in drying, smooth except the margins; _spikes_ 5--20, scattered, spreading; rhachis rough on the margins; _glumes awn-pointed_, especially the middle one (its awn about ' long), strongly serrulate-hispid on the keel, _the lower equalling the upper_, whose strong midrib abruptly terminates below the membranous apex.--Banks of rivers and lakes, or in rich soil, especially northward.

Aug.

2. S. polystachya, Willd. (SALT REED-GRa.s.s.) _Culm tall and stout_ (4--9 high, often 1' in diameter near the base); _leaves broad (--1'), roughish underneath_, as well as the margins; _spikes 20--50, forming a dense oblong raceme_ (purplish); _glumes barely mucronate, the lower half the length of the flowering one_, of which the rough-hispid midrib reaches to the apex.--Salt or brackish marshes, within tide-water, especially southward.

3. S. juncea, Willd. (RUSH SALT-GRa.s.s.) _Culms low_ (1--2 high) _and slender; leaves narrow and rush-like, strongly involute, very smooth; spikes_ 1--5, on very short peduncles, the rhachis smooth; _glumes acute_, the lower scarcely half the length of the middle one, not half the length of the upper.--Salt marshes and sea-beaches. Aug. (Eu.)

[*][*] _Spikelets loosely imbricated, or somewhat remote and alternate, the keels only slightly hairy or roughish under a lens; spikes sessile and erect, soft; leaves, rhachis, etc., very smooth; culm rather succulent._

4. S. stricta, Roth. (SALT MARSH-GRa.s.s.) (Pl. 9, fig. 1--3.) Culm 1--4 high, leafy to the top; leaves soon convolute, narrow; spikes few (2--4), the rhachis slightly projecting beyond the crowded or imbricated spikelets; glumes acute, very unequal, the larger 1-nerved, a little longer than the flower.--Salt marshes, Penn., etc.--Odor strong and rancid. (Eu.)

Var. glabra, Gray. Culm and leaves longer; spikes 5--12 (2--3' long); Spikelets imbricate-crowded.--Common on the coast.

Var. alterniflra, Gray. Spikes more slender (3--5' long), and the spikelets remotish, barely overlapping, the rhachis continued into a more conspicuous bract-like appendage; larger glume indistinctly 5-nerved; otherwise as in the preceding form, into which it pa.s.ses.--Common with the last; also Onondaga Lake, _J. A. Paine_.

2. BECKMaNNIA, Host. (Pl. 16.)

Spikelets jointed upon the pedicels, 1--2-flowered (only one fertile), obovate and laterally compressed, imbricated in 2 rows upon one side of the angled rhachis of a spike. Glumes 3 or 4, the 2 lower strongly concave and carinate, obtuse or acutish, the 1 or 2 flowering glumes narrower, lanceolate, acute or ac.u.minate and a little exserted, becoming rather rigid and with the thin palet enclosing the oblong grain.--A stout erect subaquatic perennial, with the short spikes erect and simply spicate or in a strict narrow panicle. (Named for _John Beckmann_, professor of botany at Goettingen.)

1. B. erucaeformis, Host, var. uniflra, Scribn. Glumes 3 and spikelets 1-flowered; spikes (6" long or less) panicled.--N. W. Iowa, W. Minn., and westward. The Old World form, which also is found in the far northwest, has 2-flowered spikelets.

3. PaSPALUM, L. (Pl. 13.)