570 ORDER CXLIL — GRAMINACE.E. 



Order CXLIL— GRAMINA'CEiE. (Grass Family) 



Flowers usually perfect, sometimes monoacious or polyga- 

 mous ; the exterior floral envelopes called glumes, the interior 

 ones palece, and the innermost at the base of the ovary, scales. 

 Glumes usually 2, sometimes single, usually unequal. Palece 

 2 ; the exterior one simple, the interior or uppermost usually 

 keeled. Scales 2 or 3, sometimes wanting. Stamens hypogy- 

 nous, 1 — 6. Anthers versatile. Ovary simple. Styles 2, 

 rarely 1 or 3. Stigmas hairy or plumose. Albumen farina- 

 ceous. Embryo on one side of the albumen. Culms cylindri- 

 cal, fistular, jointed. Leaves with a split sheath. 



ANALYSIS. 



1. Spikelets 1 -flowered 2 



Spikelets more than 1 -flowered 17 



2. Flowers in panicles 8 



Flowers in spikes 18 



8. Glumes not present 4 



Glumes present 5 



4. Stamens 6, monoecious Zizania, 3 



Stamens 1 — 3 Leersia, 1 



5. Glumes minute 6 



Glumes not minute 7 



6. Stamens 6 Oryza, 2 



Stamens 3 Muhlenbergia, 17 



7. Paleae awced 8 



Paleae not awned Agrosiis, 18 



8. Lower paleae with 3 awns Aristida, 16 



Lower palea3 with only 1 awn 9 



9. Paleae herbaceous 10 



Palete membranaceous or cartilaginous 11 



10. Stamen 1 Cinna, 18 



Stamens 3 , Calamagrostis, 20 



11. Paleae membranaceous AgrostU, 1 8 



Paleae cartilaginous 12 



12. Fruit black Stipa, 15 



Fruit white Oryzopsi.% 14 



13. Flowers in unilateral spikes 14 



Flowers in cylindrical spikes 16 



14. Paleas unequal Spartina, 23 



Paleae equal 15 



15. Glumes unlike 3Tanisurus, 40 



Glumes orbicular Paspalum, 9 



Glumes lanceolate Cynodon, 19 



16. Paleae 2, shorter than the glumes, without awns Phleum, 6 



Paleae 1, equal to the glumes, awned at the base Alopecurus, 5 



Paleae 2, the lower one awned Ilurdeum, 38 



17. Spikelets 2-flowcred, flowers unlike 18 



Spikelets 2-flowered and alike, or many-flowered 24 



IB. Inflorescence paniculate 19 



Inflorescence in unilateral spikes 22 



Inflorescence not in unilateral spikes 23 



