Order 15C— GRAMINE^E. • 771 



TRIBES AND GENERA. 



8 Spikelet 1-flowered with no apparent rudiment of a second 3. (2) 

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



§ Spikelet 3-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) Tribe 1 



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



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



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



— awnless. (g) Tribe 5 



5 Spikes cylindrie, the spikelets condensed all around, (e) Tribe 3 



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



6 Spikelets rounded on the back, appressed to the rachis. (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) f 



—Fls. paniculate, (k) Tribe 7 



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-rowcd, — equilateral spikes, (v) Tribe 'J 



— 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 T 



Tr. 1. ORYZE.E. (Spikelets 1-flowered, panicled. Gls. obsolete. Stam. 1— C.) 



a Flowers perfect, flattened laterally, awnless. — GI. 0. Stam. 2 or 3 Leersia. 1 



— Gl. minute. Stam. 6 Oryza. 2 



a Flowers moncccious, convex on the back, awned. Stamens 6 Zizania. ;! 



Tr. 2. AGROSTIDE^E. (Spikelets I -flrd., panicled. Gl. and pales thin. Grain free.) 



b Fls. surrounded at base with a tuft of long, silky hairs Calamagrostis. 3 



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



C Glumes both long-awned and longer than the awned pales Poi.ypogox. 5 



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



C Glumes awnless, conspicuous, (d) 



d Pale stalked in the glumes, awned on the back, monandrous Cinna. 6 



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



— obtuse, often awned on the back. . . .Agrostis. 4 



Tit. 2. PIILEOIDEjE.— e Gls. united at base, awnless. Pale 1, awned Alopecurus. 10 



— e Gls. distinct, mucronate. Pales 2, awnless Piileum. 11 



Tr. 4. STIPAOEiE. — f Awn of the flower simple, straight, deciduous Okyzopsis. 14 



— f Awn of the flower simple, twisted, very long Stipa. 1') 



— f Awn of the flower triple or 3-parted Aeistida. '13 



Tn. 5. PANICIE^E. (Spkl. 2-fl., lower il. abortive. Gls. very unequal. « Tale coriaceous.) 

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



supplying its place. — Fls. spicate, unilateral Paspalum. 1"> 



— Fls. diffusely panicled, all alike Millium. 10 



— Fls. paniculate, 2 sorts, one under ground. . . .Ampiiicaepum. 17 

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



h Fls. paniculate, — without awns or spines. Gl. very unequal Pantcum. 13 



— with the glumes and pale coarsely awned Oplismekus. 19 



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



— each with a hardened, burr-like invol CeNCHBUS. 21 



Tr.' 6. PLALARIDE^E.— i Sterile fls. 2 minute rudiments. Panicle spicate Piialaris. 22 



— i Sterile fls. 2 awned pales. Panicle spicate Antiioxanthum. 23 



— i Sterile fls. both 2-valved, £ . Panicle open IIiEROcirLOA. 24 



Tr. 7. AVENEyE. (Spkl. 2— 00 -flrd., panicled. Gls. large. Pale awned below the tip.) 



k Spikelet with 1 perf. flower and 1 awned stam. flower— above Holctts. 25 



— below § Arriiexatherum. 23 



k Spikelet with definitely 2 perfect fls. Palo subentire. awn dorsal Aira. 2<> 



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



