28 



GRAMINEiE. 



Perfect flower solitary, without empty bractlets or staminate flowers either 

 above or below it. 

 Bractlet with a dorsal awn arising from below the middle, or awnless. 

 Awn sometimes obsolete, when present straight, not twisted 



4. AGROSTIDEjE, p. 37. 



Awn always present, geniculate and twisted:— some forms of 



Deschampsia and Trisetum in 5. Avene.e, p. 48. 



Bractlet with a terminal awn (sometimes very short):— some species of 



Kceleria and Festuca in 7. Festuce.e, p. 57. 



Perfect flower with one or two staminate flowers or empty bractlets below 

 (rarely above) it. 



Spikelet with 2 staminate flowers or 2 empty bractlets below the perfect 

 flower:— Anthoxanthum and Hierochloe in 3. Phalaride^e, p. 33. 



Spikelets with only 1 staminate flower (never empty bractlets) below or 

 above the perfect flower:— Arrhenatherum and Holcus in 



5. AvenejE, p. 48. 



Spikelets with 1 or 2 empty bractlets above the perfect flower: — Melica, 



Koeleria and Festuca in 7. Festuce-E, p. 57. 



Spikelets sessile or very shortly pedicellate; arranged in two close, crowded 

 rows forming 1-sided spikes or racemes: these racemes digitate or fascicu- 

 late, rarely solitary: rachis not breaking up at the nodes 



6. Chloride-e, p. 55. 

 Spikelets arranged in 2 opposite rows, forming a 2-sided spike or raceme; 



sessile or very shortly pedicellate on teeth, or in notches or grooves of the 

 rachis which is often flexuous; rachis in many cases jointed at the nodes, 

 each internode at maturity falling away with the attached spikelet. . . . 



8. Horde.e, p. 72. 



B. Spikelets with 2 or more perfect flowers (dioecious in 8. Festucese in the 

 genus Distichlis and sometimes in Poa and Pliragmites); imperfect flowers, 

 when present, uppermost (except in Phragmites and rarely in Eragrostis). 

 Spikelets pedicellate, arranged in lax or more or less dense and spikelike 

 panicles or racemes; when in racemes or spikes not in opposite rows on 

 the rachis. 



Bracts large in proportion to the whole spikelet, usually enclosing all the 

 flowers; one or more of the bractlets bearing a twisted and abruptly bent 

 awn, usually on the back, rarely from between the teeth of the bifid 

 apex or awnless; when not awned there are 2 nearly opposite flowers, 

 and the rachilla is not prolonged beyond them; in Avena sativa the 

 awn is often obsolete or straight, though the flowers are more than 2 

 and not opposite * 5. AvenejE, p. 48. 



Bracts small in proportion to the whole spikelet, usually scarcely exceeding 

 the apex of the first flower; bractlets awnless, or with 1 to 3 straight awns, 

 which are usually terminal, or rarely borne just below the apex .... 



7. FesttjcEjE, p. 57. 



Spikelets arranged in 2 opposite rows, forming a bilateral spike or raceme; 

 sessile or shortly pedicellate on teeth, or in notches or grooves of the 

 rachis which is often flexuous; rachis in many cases jointed at the nodes, 

 each internode at maturity falling away with the attached spikelet. . . . 



8. Horded, p. 72. 



Tribe 1. Andropogoneae. Sorghum Tribe. 



Inflorescence a simple or compound panicle, the ultimate branches 

 of which consist of spikelike racemes of few or many spikelets. 

 Eachis usually jointed at the nodes. Spikelets in pairs at each node, 

 or in triplets at the end of each raceme, of two kinds, one of each pair 

 sessile and perfect or polygamous, the other pedicellate and imperfect, 

 rudimentary, or reduced to the pedicel; pedicel and callus often 

 clothed with long silky hairs; spikelets generally with but one flower, 

 usually with a hyaline empty bractlet" below it, or rarely the latter 

 hearing a staminate flower in its axil, or obsolete. Lower bract 

 always more indurated than the bractlets, the latter often hyaline and 



