POACEAE. 



9 



Anthers 2-ceI ed, versatile. Ovaiy 1-eelled, 1-ovuled. Styles 1-3, eom- 

 monly 2 and lateral. Stigmas hair^ or plumose. Fruit a Led-like TaTn 

 (earyopsis) Endosperm starchy. About 3500 species widely distributed 

 throughout the world, growing in water and on ill kinds of soil T ose 

 yielding food-grams are called cereals. The species are more numerous in 

 tropical countries while the number of individuals is murgrea" tern 

 perate regions, often forming extended areas of turf 



B. 



Inflorescence of clustered racemes ^^"^^^^'''ng tne otliers. (Andropogoneae.) 

 Inflorescence paniculate, decompound o iJ^^^'<^Poyon. 



ceae":)^ ^ ^'^^^^^'' ^^^"^ ^^^ °^^^'^' ^^ wanting. (Pam- 

 ^* ^*^l^ll^^i^ ^""^ sunken in the rachis of a spike. 



intoluSe ''''^ subtended by bristles or by an 

 t Outer scales of the spikelets awnless. 

 bpikeJets obtuse, in spike-like racemes 

 Spikelets acute, in spike-like racemes, or 

 panicled. ' 



Second scale not saccate 

 - Second scale saccate at base, large, manv- 

 nerved. ' "^'^"J' 



Spikelets long-silky; fruiting scale lan- 

 ceolate. 

 Spikelets short-pubescent or glabrous • 

 4.4. ^ X fruiting scale elliptic. 



TT Outer scales of the spikelets awned 

 Third scale with the longest awn. 

 ** o •, I "5^ ^^.^^^ w*t^ <^^e shortest awn. 



i^voP r" °*^^^ ^^ "^ °^ ^""^^ bristles or by an 

 Spikelets subtended by persistent bristles. 



''Suous';i?h'^'t'" ^ '"^^^^' ^^^^^ ^^^^'--• 



2. Spikelets sunken in the thick rachis of a flat spike 

 Spikelets articu ated above the empty scales or between the 

 flowering scales, 1-many-flowered ueiweeu me 



^" ^'i^-ll^^ panicled or racemed, or if spicate, not In depres- 

 sions of the rachis of the spike. 

 1. Spikelets not in 2-rowed secund spikes 

 * Spikelets 1-flowered. 



t Empty scales 4. (Phalarideae.) 

 tt Empty scales 2. (Agrostideae.) 



Empty scales of the spikelet persistent, the 

 flowering scales deciduous. 

 Empty scales awned. 

 Empty scales awnless, 

 ** c ..Spikelets wholly deciduous at maturity 

 ** Spikelets 2-many-flowered. 



Flowering scales shorter than the empty ones the 



awn dorsal, usually bent. (Avexeae ) 

 Flowering scales mostly longer than the empty 

 ones, the awn, if present, straight, terminal 

 (Festuceae.) 

 Flowering scales long-hairy ; very tall grass 1 7 



Flowering scales not long-hairy flow grasses 

 Flowering scales 1-3-nerved. 



Panicle-branches distichous. 18 



Panicle-branches spirally arranged. if)' 



Flowering scales 5-many-nerved. 



Flowering scales cordate. 20 Briza 



Flowering scales not cordate. 



Stigmas borne at or near the apex 

 of the ovary. 

 Flowering scales keeled on the 

 ^ back. 21. Poa. 



Flowering scales rounded on the 

 back, at least below. 

 Inflorescence a short-branched 



panicle. 22. Sclcropoa. 



Inflorescence a simple or 



branched spike. 23. Desmazeria. 



2. Holcus. 



3. Paspalum. 



4. Panicum. 



5. Valota. 



6. Syntherisma. 



7. Echinochloa. 



8. Oplismenus. 



9. Chaetochloa. 



10. Cenchrus. 



11. Stenotaphrum. 



12. Phalaris. 



Phleum. 



Sporobolus. 



Polypogon. 



16. Avena. 



Arundo. 



Kochlcria. 

 Era(jrostis. 



