GRASSES OK IOWA. 



4:] 



«, I'anicum ^inguinale, b, Panicum capillar e. 



Fig. 1. a, Panicum Sanguinale spikelet with three lower glumes, stamens and pistil(after 

 Gray) ; b, Panicum Capillare spikelet with parts of the flower. (Charlotte M. King. ) 



KEY TO THE GENERA OF THE PANICE^E. 



Spikelets not subtended or surrounded by an involucre of bristles or spines; 

 perfect flower one. 



Empty glumes two Paspalum. ' 



Empty glumes three, or two and the third glume staminate. . . Panicum " 

 Spikelets subtended or surrounded by an involucre of one to many bristles 

 or spines. 

 Involucral bristles persistent, the spikelets falling out at maturity. 



— Setaria. 

 Involucral bristles falling off with the spikelets at maturity. 



Bristles numerous, thickened or united below into a bur-like 



structure Cenchrus. * 



Bristles numerous, not thickened, delicate, plumose Pennisetum. 1 ' 



1. PASPALUM. 



Pispaluw L. Syst. 2: 855 17. ; 9. [Ed. 10.] Endlicher Gen PI. 82. Hackel 

 in Engler & Prantl. Nat. P,lanz Fam. II. 2: 33. /. 24. Bentham & Hooker. 

 Gen. PI. 3: 1097. Scribner Bull. U. S Dept. Agrl Uiv. A'<ios 20: 33. (Rev.) 



Spikelets spiked or somewhat racemed, in 2-4 rows on one side of a 

 flattened or filiform continuous rachis, jointed upon very short pedicels, 

 plano-convex, awnless, i-flowered. Glumes 3 (rarely only 2) the ter- 

 minal one flowering. Flower coriaceous, mostly orbicular or ovate, flat 

 on the inner side, convex on the outer. Stamens 3. Spikes one or more, 

 at or toward the summit of an elongated peduncle. (From the Greek 

 name for Millet.) 



Bentham & Hooker give the number of species as 160. Hackel 

 gives the number as 38. Found chiefly in warm temperate regions in 



