ORDER 156. GRAMINE.E. 771 



TRIBES AND GKNERA. 



5 Spikclct 1-flowered with no apparent rudiment of a second fl. (2) 

 Spikelet 2-flowered, one of the fls. sterile or rudimentary. (7) 



S|.ike!et3-flowered, the 2 lower (lateral) fls. sterile or rudimentary, (i) .Tribe 6 



Spikelet 2 00 -flowered, 2 or more of the fls. perfect. (9) 

 2 Inflorescence paniculate. (3) 



2 Inflorescence strictly spicate, spikes equilateral. (5) 

 2 Inflorescence strictly spicate, spikes unilateral. (6) 



3 Glumes none (or minute and the stamens 6). (a) Trlbo 1 



3 Glumes present, at least 1 conspicuous. (4) 



4 Pales of the flower thin and soft, often awned. (b) Tribe 2 



4 Pales of the flower coriaceous, tipped with awns, (f ) Tribe 4 



awnless. (g) Tribe 5 



5 Spikes cylindric, the spikelets condensed all around, (e) Tribe :: 



5 Spikes prismatic, spikelets sessile in rows, (v) Tribe 9 



6 Spikelets rounded on the back, impressed to the rachts. (g) Tribe 5 



6 Spikelets acutely keeled on the back, imbricated on each other, (x) ) ., 



7 Upper fls. of the spikelet abortive. Fls. in unilateral spikes, (x) } '" 



Fls. paniculate, (k) Tribe 1 



7 Lower flower of the spikelet abortive. (8) 



8 Pales coriaceous, firmer in texure than the gls. Paniculate, (g) Tribe 5 



8 Pales membranous, thinner than the glumes. Spicate. (bb) Tribe 11 



9 Flowers in 2 or 4-rowed, equilateral spikes, (v) Tribe 9 



unilateral spikes, (x) Tribe 10 



9 Fls. in panicles more or less diffuse. (10) 



10 Pale awncd at the tip or awnless. (n) Tribe S 



10 Pale awned on the back or below the tip. (k) Tribe 7 



Tit. 1. OETZE.-E. (Spikelets 1-flowered, panicled. Gls obsolete. Stam. 10.) 



a Flowers perfect, flattened laterally, awnless. Gl. 0. Stain. 2 or 3 LEERSIA. 1 



Gl. minute. Stam. 6 ORYZA. 2 



a Flowers monoecious, convex on the back, awned. Stamens C ZIZANIA. S 



TR. 2. AGUOSTIDE.E. (Spikelets 1-flrd., panicled. Gl. and pales thin. Grain free.) 



b Fls. surrounded at base with a tuft of long, silky hairs CALAMAGEOSTIS. 9 



b Fls. naked or thinly bearded at base, (c) 



C Glumes both long-awned and longer than the awned pales POLYPOGOX. 8 



C Glumes both awn-pointed (or minute and the pale awned) MUHLENBERGIA. 7 



C Glumes awnless, conspicuous, (d) 



d Pale stalked in the glumes, awned on the back, monandrous CIXXA. C 



d Pale sess. in the gls. 3-androus, acute, awnless. Gls. shorter SPOKOBOUJS. 5 



obtuse, often awned on the back AGKOSTIS. 4 



Tit. :j. PlILEOIDE^E. e Gls. united at base, awnless. Pale 1, awned ALOPECURUS. 1(1 



e Gls. distinct, mucronate. Pales 2, awnless PHLEUM. 11 



Tit. 4. STIPACE^E. f Awn of the flower simple, straight, deciduous ORYZOPSIS. 14 



f Awn of the flower simple, twisted, very long STIPA. 13 



f Awn of the flower triple or 3-parted ARISTIDA. 12 



TR. 5. PANICIK^L (Spkl. 2-fl., lower fl. abortive. Gls. very unequal, e Pale coriaceous.) 

 g Spkl. apparently 1 -flowered, the lower glume wanting and the single abortive pale 



supplying its place. Fls. spicate, unilateral PASPALUM. 15 



Fls. diffusely panicled, all alike MILLIUM. 1C 



Fls. paniculate, 2 sorts, one under ground AIIPHICABFUM. IT 



g Spkl. evidently 2-flowered. both gl. present, abort, fl. neutral or S . (h) 



h Fls. paniculate, without awns or spines. Gl. very unequal PAKICUM. IS 



with the glumes and pale coarsely awned OPLISMENUS. 19 



h Fls. spike-panicled, each with an invol. of awned pedicels SETAEIA. 20 



each with a hardened, burr-like invol CENCHRUS. 21 



TE. 6. PHALARIDE^E.-i Sterile fls. 2 minute rudiments. Panicle spicate PIIALARIS. 22 



i Sterile fls. 2 awned pales. Panicle spicate. .. .ANTHOXANTIUJM. 23 



i Sterile fls. both 2-valved, $ . Panicle open HIBROCIILOA. 24 



TR. 7. AVENE,. (Spkl. 2 00 -flrd., panicled. Gls. large. Pale awned below the tip.) 



k Spikelet with 1 perf. flower and 1 awned stam. flower above HoLcrrs. !5 



below ARRIIENATIIERtTM. 23 



k Spikelet with definitely 2 perfect fls. Palo subentire, awn dorsal AIKA. 2 



k Spikelet with 2 or more perfect fls. Pale 2-toothed at apex, (m) 



