GRAMINE^. 



430 



^ i% 



S i 



Spikelets 2 — 30-Jloivered ; when but 2-Jlotvered botk perfect or both staminate. 



f apex entire. Sta. 2. Anthoxanthum. 

 \ apex bifid. Awn bent. Avena. 

 near the base ;' apex multifid. . Aira. 



J which has 2 bristly teeth. Trisetum. 

 on tlie back ( near the apex ( which is merely bifid. Bromus. 

 i withlong:, silky hairs. Arundo. 

 f which is entire j and naked. . . Festuca. 

 Lower "j J between the 2 teeth ; awn twisted. Do.nthoma. 



pnlea; I 1 which is tricuspidale. . . . UraUpsh. 



awned . .. [ at tlie apex [which is eroded. Perfect fl. diandrous. Hitrochloa. 



STer. ped. ( Ovary with 2 scales. Poa. 

 flowered. ( Ova. adnate to ^n.\stp..Fe.<,tuca. 



Lower 



palen; 



awnlesi 



Knleria. 



XJniola. 



Briza. 



■Glyceria. 



Triaispis. 



Lolium. 



Trlticum. 



ovate. . . ( Terminal pedicel flowerless 

 Spikelets acute at base, flat, ancipital. 

 ■ entire. \ Spikelets cordate at base, tumid. . 

 I denticulate. Spikelets terete, linear. Aquatic. 

 , bifid and trieuspidate by the projecting nerves. 

 f Glumes ( 1 (in the top spikelet 2). 

 J broad, ( 2 in each spikelet. 

 I" Spikes 1 Gl.sub- | collateral. Spikelets in2s,&c. Elymus. 

 J 2-ranked. [ulate, . J opposite. Spikelets solitary. Secale. 

 Inflorescence ) j paniculate. Scarcely awned. Dac.tylis. 



spicate [ Spikes unilateral, | digitate. Palea; awiiless. Eleusine. 



Stem solid with ( Spikes terminal, digitafe, pistillate at base. . lYipsacum. 

 pith. Monoecious. ( Spikes lateral, pistillate ; panicle term, staminate. Zea. 



Tribe 1, STIPACE^. 



Inflorescence panicled. Spikelets solitary, 1-floivered. Ghtmes membranaceous. PalecB mostly 

 two, lower one coriaceous, intyolute, awned. 



1. ARISTl'DA. 

 Glumes 2, unequal; paleas pedicellate, lower one with 3 

 awns at the tip, upper one very minute or obsolete. 



1. A. dicho'toma. Poverty Grass. 



Casspitose ; s/c?« dichotomousty branching; p«?tiV/e contracted-racemose; 

 lateral aicns very short, the intermediate one nearly as long- as the paleas, con- 

 torted. A slender grass, in sandy soils. Stems 8— 12 inches high, branching 

 at each joint. Leaves very narrow, with very short, open sheaths, and a 

 very short stipule. Spikelets slender, on clavate peduncles. Aug. 



2. A. purpura'scens. Poir. 



Stem erect, simple, filiform, 2 — 3 feet high ; leaves very narrow, flat, erect, 

 a foot in length, with short, open sheaths ; panicle long, loosely spicate ; spike- 

 lets on short clavate, appressed pedicels ; aicns nearly equal, divaricate, twice 

 the length of the paleae ; jialea: often dark purple. Sandy woods. Sept. 



3. A. gra'cilis. Ell. 



Stem very slender, a foot or more high ; leaves setaceous, erect, with short 

 sheaths, pilose at the throat; panicle very slender ; spikelets somewha.t re- 

 mote, appressed ; lateral awns siiort, erect, intermediate one longer, spreading. 

 Mass. A grass of little value, as well as the other species. 



2. STIPA. 

 Glumes 2 ; palese mostly 2, shorter than the glumes, the 

 lower with a long awn at the apex, the upper entire ; awn 

 jointed at the base, deciduous ; caryopsis striate. 



1. S. avena'cea. Feather Grass. 



Stem naked above, 2 — 3 feet high ; leaves smooth, striate, setaceous, chiefly 

 radical; particle spreading, somewhat 1-sided, 4 — 6 inches long, at length 

 diffuse, branches capillary, solitary and in pairs; glumes nearly equal, 

 mucronate, as long as the dark brown, cylindric fruit; scales 2, lanceolate. 

 Sandy soils. Mass. N. Y. June. 



