ORDER 155. GR AMINES 381 



8 Inflorescence paniculate. ..(3) 



2 Inflorescence strictly spicate, spikes equilateral... 



2 Inflorescence strictly spicate, spikes unilateral... (6) 



3 Glumes none (or minute and the stamen* 6)... (a) Tribe 1 



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



4 Pales of the flower thin and soft, often awned... (6) Tribe 2 



4 Pales of the flower coriaceous, * tipped with awns... (/) Tribe 4 



* awnless...(<7) Tribe 5 



ft Spikes cylindric, the spikelets condensed all around. . .(e) Tribe 3 



ft Spikes nrismatic, spikelets sessile in rows . . . (v) Tribe 9 



6 Spikelets rounded on the back, appressed to the rachis...(0) Tribo 5 



6 Spikelets acutely keeled on the back, imbricated on each other. . .(x) ) Tribe 10 



7 Upper hs. of the spikelet abortive.* Fls. In unilateral spikes... (x) ' " 



* Flowers paniculate... (fc) Tribe 7 



7 Lower flower of the spikelet abortive... 



8 Pales coriaceous, firmer in texture than the glumes. Paniculate... (y) Tribe 5 



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



9 Flowers in 2- or 4-rowed, * equilateral spikes... (c) Tribe 9 



* unilateral spikes. ..(x) Tribo 10 



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



10 Pale awned at the tip or awnless... (71) Tribe 8 



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



L ORYZE.E. (Spikelets \-floicered, jrsmided. Glumes obsolete. Stamens 16.) 



a Flowers perfect, flattened laterally, awnless. Glumes 0. Stam. 2 or 3. Cut Grass LKERSIA. 1 



Glumes minute. Stamens 6. Rice ORYZA. 2 



a Flowers monoecious, both kinds in the same panicle. Stamens 6. IiidianRice. ZIZANIA. 3 



a Flowers monoecious, each kind in separate panicles. Stamens 5 12. S LUZIOLA. 4 



i. AGROSTIDEiE. (Spikelets 1-jloicered, pnnided. Glumes and pales thin. Grain free.) 



b Flowers surrounded at base with a tuft of long, silky hairs CALAMAGROSTIS. 10 



6 Flowers naked or thinly bearded at base. . .(c) 



c Glumes both long-awned and longer than the awned pales POLYPOGON. 9 



e Glumes both awn-pointed (or minute and the pale awned) MUHLE.NBKHGIA. 8 



e Olumes awnless, conspicuous. . .(d) 



d Pale stalked in the glumes, awned on the back, monandrous. Siceet Reed CIHNA. 7 



d Pale sess. in the glumes, 3-androus, acute, awnless. Glume? shorter SPOKOBOI.US. 6 



obtuse, often awned on back. Sent (^..AGROSTIS. 5 



3. PHLEOIDE^E. e Glumes united at base, awnless. Pale 1, awned ALOPECCKUS. 11 



e Glumes distinct, mucronate. Pales 2, awnless. Timothy PHLECM. 12 



e Glumes distinct, pointless. Pales 2, awnless CRYPSIS. 13 



4. STIPACE^E. / Awn of the flower simple, straight, deciduous ORYZOFSIS. 16 



/ Awn of the flower simple, twisted, very long STIPA. 15 



/ Awn of the flower triple or 3-parted. Poverty Grass ARISTIDA. 14 



C. PANICE^E. (Spikeletx 2-fltcd., loicer floicer abortive. Glumes eery unequal, g Pale coriaceoui.) 

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



supplying its place. Flowers spicate, unilateral PASPALCM. 17 



Flowers diffusely panicled, all alike. Millet Grass M ILIUM. 18 



Flowers paniculate, 2 sorts, one under ground AMPHICARPUM. 19 



g Spikelet evidently 2-flowered, both glumes present, abortive flower neutral or ...(h) 



h Flowers paniculate, without awns or spines. Pale cartilaginous. Panic G PANICUM. 20 



without awns or spines. Pales herbaceous PENICILLARIA. 21 



with the glumes and pale coarsely awned. Cock-spur. . .OFLISMENUS. 22 



h Flowers spike-panicled, each with an invol. c.f awned pedicels. Fox-tail SETARIA. 23 



each with a hardened, burr-like invol. Burr Grass... CENCHRUS 24 



I PUALARIDE,. i Sterile flowers 2 minute rudiments. Panicle spicate PHALARIS 25 



i Sterile flowers 2 uwued pales. 1'anicle spicate-^ ~ ~ ^AxrnoxA-jmiuM 26 



t Sterile flowers both 2-valved, ( . Panicle open HIEROCELOA. 27 



/. AVENE^E. (Spikelets 2 - OO -floicered, panicled. tilumet large. Pale aicncd below thf tip.) 



ft Spikelet with 1 perfect flower and 1 awned staminate flower above. So/I Grass HOLCUS. 28 



below ARRHKXATHKRUM. 31 



* Spikelet with definitely 2 perfect flowers. Pale subentire, awn dorsal AIRA. 2J 



A Spikelet with 2 or more perfect flowers. Pale 2-toothed at apex. . .(w) 



