214 



OKDER CXL. QEAMINE^5 GRASS-FAMILY. 



** Spikelets in panicles, often much contracted, 

 and apparently racemose. 



t Paleae, awnless or with inconspicuous awns. 



4. AGRUSTIS. Glumes equal, or the lower somewhat longer. Palese thin, 

 not coriaceous, obtuse, upper smaller ; one often minute or wanting. Stamens 

 usually 8. 



5. CINXA. Lower glume somewhat shorter than the upper one; lower 

 palea with a short, inconspicuous awn on the back below the tip ; upper palea 

 1-nerved. Stamen 1. 



6. MUHLENBERGIA. Glumes usually acute or mucronate ; lower one smaller, 

 often minute, usually shorter. Palese mostly shorter than the glumes, sur- 

 rounded by short hairs at base ; lower 3-nerved, usually mucronate. Stamens 3. 



8. CALAMAGROSTIS. Spikelets with a rudimentary, plumose pedicel. Glumes 

 mostly nearly equal, longer than the flower. Palese surrounded at base by 

 a tnft of white bristles ; lower palea awnless, or with a rather inconspicuous awn 

 attached to the back. Stamens 3. 



81. MiiiuM. Spikelets without any rudimentary pedicel ; glumes apparently 

 2, equal. Paleae 2, coriaceous Stamens 8. 



80. PHALARIS. Spikelets with 2 rudiments of abortive flowers, 1 on each 

 side of the perfect flower. Paleae shorter than the equal glumes. 



1 1 Palece with a conspicuous awn. 



8. MUHLENBERGIA. Lower glume smaller than the upper, sometimes 

 minute. Paleae 2, herbaceous. Awn of the lo\vr palea single, not jointed on 

 its apex. 



7. BRACIIYELYTRUM. Spikelets with the filiform pedicel of an abortive 

 flower lodged in the groove of the emarginate, upper palea; lower glume none ; 

 upper minute. Stamens 2. 



9. ORYZOPSIS. Glumes nearly equal. Paleae equal ; lower coriaceous, en- 

 veloping the upper, with the awn jointed on to the apex. Stamens 3. 



10. ARisTiDA. Gl nines not equal, often mucronate. Lower palea with 3 

 awns at tip, much larger than the upper. 



* * * Flowers, primarily at least, arranged in simple 

 or nearly simple spikes. 



t Spike simple or nearly simple, terminal. 



8. PHLEUM. Spike simple, dense, cylindrical. Glumes mucronate or awned. 

 Paleae both present, awnless. 



24. HORDEUM. Spikelets in threes at each joint of the rachis. Glumes side 

 by side, mucronate, awned. Lower palea awned at apex. 



1 1 Spikes more than one. 



11. SPARTINA. Spikes very densely many-flowered; few or many, in a 

 terminal raceme. Glumes acute or awned ; upper one larger than the awnless 

 paleae. 



32. PASPAI.UM. Spikelets loosely arranged in 2 4 rows, on one side of the 

 flattened rachis, orbicular. Spikes few. 



33. PANICUM. Flowers oblong, crowded in clusters of 2 3, in 1-sided, ap- 

 proximate, slender spikes. 



S. Spikelets really 2-flowered, the upper perfect, the lower staminate or 

 neutral, and in the latter case usually reduced to a single palea, so that the 

 flower appears to have 2 glumes andSpaleai. 



33. PANICUM. Spikelets single, with the terminal flower perfect, not sur- 

 rounded by bristles, arranged in racemes, panicles, or compound spikes. 



34. SETARIA. Spikelets surrounded by several or many bristles, and ar- 

 ranged in a cylindrical more or less compound spike. 



85. ANDROi'dooN. Spikelets in pairs, one pedicellate and sterile ; the other 

 with the terminal flower perfect and awned, all arranged in spikes or racemes. 



36 SORGHUM. Spikelets in clusters of 2 3, 1 only with the terminal flower 

 perfect and awned, the others sterile or mere rudimentary pedicels ; all ar- 

 ranged in panicles. 



37. ZEA. Flowers monoecious ; barren flowers in terminal, numerous spikes ; 

 fertile in solitary, lateral spikes, inclosed in a leafy involucre of numerous bracts. 

 Styles long and slender, much exsert. 



C Spikelets really 3-flowered, 2 of them imperfect or abortive, mostly 

 reduced to single palece. 



28. H6LCHS. Spikelets in contracted panicles; lower flower abortive or 

 obsolete ; middle flower perfect; upper flower staminate. 



29. ANTHOXANTIIUM. Spikelets in nearly simple, cylindrical spikes ; the two 

 lateral flowers neutral, reduced to awned palcre ; middle flower perfect, with 

 awnless palea. 



D. Glumes containing more than 2 flowers, or if only 2 both are perfect. 



* Spikelets in panicles which are often much con- 

 tracted nnd spike-like. 



t Lower palea with a conspicuous awn. 



12. DACTYLIS. Spikelets 3 6-flowered, in dense, 1-sided clusters, forming a 

 crowded panicle. Glumes awned, somewhat rough and ciliate on the back, as 

 also the lower palea. 



17. FESTUCA. Spikelets 810 flowered, in open panicles, or contracted, 

 spicate ones. Glumes unequal. Palese rounded on the back, entire, awned at 

 the apex. 



18. BROMITS. Spikelets 5 12 flowered, in loose, at length drooping panicles. 

 Glumes unequal. Lower palea mostly 2-cleft, with a straight awn below the tip. 



25. AJRA. Spikelets with 2 perfect flowers, rarely a third imperfect one. 

 Flowers hairy at base. Lower palea awned on the back below the middle. 



26. DANTiidxiA. Spikelets 7-flowered, in a loose, racemose panicle. Lower 

 palea 2-toothed at apex, with an awn composed of the three twisted nerves 

 rising from between the teeth. 



27. AVENA. Spikelets 8 6-flowered; uppermost imperfect Glumes nn- 



eqnal. Lower palea rounded on the back, with a twisted awn, consistingonlj 

 of the middle nerve, and arising on the back below the 2-cleft tip. 



1 1 Lower palece dtcnless. 



13. GLYCKRIA. Spikelets nearly terete, 3 13-flowered. Flowers perfect, 

 sessile, deciduous, the rachis separating into pieces at the joints. Glumes short, 

 unequal, persistent after the falling of the flowers. Paleic nearly equal ; lower 

 7-veined. 



14. BRIZOPYRUM. Dioecious. Spikelets compressed, 5 10-flowered, in a 

 dense, spicate panicle. Leaves re volute. 



15. PbA. Spikelets compressed, 2 7-flowered, in open panicles, clothed 

 with more or less of a web-like down, but not bearded at base. Upper palea 2- 

 toothed, deciduous, together with the larger, 5-nerved, lower palea. 



16. ERAGKOSTIS. Spikelets compressed, 2 40-flowered, in open panicles, 

 not webbed or bearded at base. Paleie free from the grain ; lower palea 3- 

 nerved ; upper one persistent alter the rest of the flower has fallen. 



17. FESTtrcA. Spikelets 3 10-flowered ; flowers not webbed nor bearded at 

 base. Palete rounded on the back ; upper one adhering to the inclosed grain, 

 which is somewhat downy at apex. 



19. PHRAGMITES. Spikelets 3 7-flowered; flowers with a copious silky 

 beard at base ; lower flower neutral or with 1 stamen ; the others perfect with 

 3 stamens. Glumes very unequal. 



** Spikelets in simple, terminal spikes. 



20. TRVTICUM. Spikelets 8 10-flowcred, attached singly to the joints of the 

 rachis, with the side against it. Glumes 2, on opposite sides of the spikelet. 



21. SECALE. Spikelets solitary at each joint of the rachis, 2 3-flowered. 

 Glumes 2 opposite, subulate, shorter than the flowers. 



22. L6uuM. Spikelets 5 9-flowered, solitary at the joints, and attached 

 edgewise. Glume single on the outside of the Spikelets, except at the terminal 

 spikelet which has 2. 



23. I,YMUS. Spikelels 2 7-flowered, in clusters of 2 4 at each joint of the 

 rachis. Glumes side by side on the front of the spikelet, rarely none. 



1. LE^RSIA. 



Spikelets 1-flowered, compressed, perfect, in secund racemes, 

 arranged in panicles. Palea 2, compressed, carinate, awnless, 

 nearly equal; lower broader. Stamens 1 6. Stigmas plumose. 

 Per. 



1. L. oryzoides. Cut-Grass. 



Culm rough backwards, with hooked prickles, as also the lanceolate leaves; 

 panicle sheathed at base, with numerous diffuse branches ; stamens 3 ; palero 

 whitish, ciliate On the keel. A common and very rough grass in wet grounds, 

 well known by the hooked prickles of its stem and leaves, which are sharp, 

 rough, and readily cut the flesh. Culm 12 ft hfgh. Aug. 



2. L. Virginica. 



Wliite Grass. 



Culm slender, branching, geniculate or decumbent at base, clothed with re- 

 curved bristles at the nodes ; leaves linear-lanceolate, rough backwards, but not 

 so much as in the last ; sheaths rough backwards ; panicle simple ; flowers ap- 

 pressed on the slender branches; stamens 2; palese greenish, slightly ciliate, 

 A more slender species than the last, with the stem and leaves much less roughs 

 and a simpler panicle. Culm 15' 20' high. Aug. 



2. ZIZANIA. 



Flowers monoecious. Spikelets 1-flowered, both kinds in the 

 same panicle. Glumes mostly wanting. Paleaj of the barren 

 flowers awnless, of the fertile, with a straight awn. Stamens G. 

 Styles 2. Per. 



1. Z. aquatica. Indian Rice. 



Culm hollow, smooth, tall ; leaves flat, very long, linear-lanceolate, smooth, 

 serrulate ; panicle very large, pyramidal ; lower branches spreading, staminate ; 

 upper branches erect, pistillate ; pedicels of the pistillate flowers clavate ; lower 

 palea with a long awn ; grain linear. A tall, aquatic grass, on the shallow 

 borders of streams, and of swamps, salt or fresh. Culm 4 8 ft high. The 

 spikelets and fruit are very deciduous. Bather common. July Aug. 



S. PHLfcUM. 



Glumes 2, carinate, much longer than the palese, mucronate or 

 awned. Palese 2, unequal, truncate, included in the glumes. 

 Stamens 3. Per. 



1. P. pratense. Timothy. Herd's Grass. 



Culm erect, simple, smooth, sometimes bulbous at base ; leaves flat, glau- 

 cous; flowers in a long, dense, simple, terminal, cylindrical spike ; glumes cili- 

 ate on the back, truncate, tipped with a very short awn ; anthers purplish. A 

 very valuable species, frequently cultivated for hay, and thoroughly naturalized. 

 Culm 24 ft high. June July. 



4. AGROSTIS. 

 Spikelets 1-flowered, paniculate. Glumes 2, subequal, or the 



