GRASS FAMILY. 35 



times minute, empty bractlets or staminate flowers; bracts usually sub-equal 



3. Phalasideae, p. 39. 

 Only the bractlet firmer in texture than the bracts and becoming indurated in fruit; 



palea hyaline. 

 Awn terminal, geniculate; bractlet cylindrical-involute: — Stipa in 



4. Agrostideae, p. 43. 

 Awn dorsal, geniculate; bractlet not cylindrical-involute: — sometimes A vena in 



5. Aveneae, p. 51. 

 Neither bractlet nor palea firmer in texture than the bracts, though in Hordeae both may 

 be equally firm; often one or both of them hyaline. 

 Spikelets pedicellate; arranged in lax or more or less dense and spikelike panicles or 

 racemes; if in racemes or spikes these sometimes densely cylindrical but the spike- 

 lets not in distinct rows. 

 Spikelets of two kinds in the same inflorescence, one polygamous, the other imperfect 

 or rudimentary; two (one of each kind) or several at a node. 

 Spikelets in pairs, or the terminal in threes, at each node of the jointed rachis, 

 one (or two) pedicellate and (in ours) imperfect, the other sessile and con- 

 taining 1 perfect flower subtended by either a hyaline empty bractlet or a 



staminate flower 1. Andropogoneae, p. 36. 



Spikelets crowded at each node of a dense, 1-sided, brush-like panicle; the fertile 

 solitary, short, terminating the panicle-branches and entirely concealed by the 

 long sterile spikelets, which consist of about 10 empty bractlets: — Lamarckia 



in 7. Festuceae, p. 59. 



Spikelets all of one kind in the same inflorescence, though their contained flowers may 

 be perfect, monoecious or polygamous. 

 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. Agrostideae, p. 43. 

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



Trisetum in 5. Aveneae, p. 51. 



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



and Festuca in 7. Festuceae, p. 59. 



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

 above) it. 

 Spikelets with 2 staminate flowers or 2 empty bractlets below the perfect flower 



— Anthoxanthum and Hierochloe in 3. Phalarideae, p. 39. 



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



the perfect flower: — Arrhenatherum and Holcus in 5. Aveneae, p. 51. 



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



and Festuca in 7. Festuceae, p. 59. 



Spikelets sessile or very short pedicellate; arranged in two close, crowded rows form- 

 ing 1-sided spikes or racemes; these racemes digitate or fasciculate, rarely solitary; 



rachis not breaking up at the nodes 6. Chlorideae, p. 57. 



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. Hordeae, p. 71. 



B. Spikelets with two or more perfect flowers (dioecious in Festuceae in the 

 genus Distichlis and sometimes in Poa and Phragmites) ; imperfect flowers, when pres- 

 ent, 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 Bowers, ami 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. Aveneae, p. 51. 



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. FESTUCEAE, p. 59. 



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. Hordeae, p. 71. 



