100 GRAMINEAE ((illASS FAMILY) 



10. AXONOPUS Beauv. 



Spikelets 1-flowered, compressed bi-convex, sessile, solitary in two rows on one 

 side of a flattened rhachis (which is naked in ours), placed with the back of the 

 fertile lemma turned from the rhachis, forming simple spikes ; first glume obso- 

 lete ; lemma and palea indurated but less so than usual in /'ifxprtlitm, margins 

 of the lemma inrolled. Perennials with 2-several slender spikes digitate or 

 sub-digitate at the summit of the culm. (Name from du>j', axis; and Troys, 

 foot.} A\A<I KOIMII * Schlecht. 



1. A. furcatus (Fliigge) Hitchc. Tufted, soft, 3-10 dm. high, with long 

 creeping leafy stolons ; leaves obtuse ; racemes a pair at the summit of the culm, 

 7-10 cm. long ; spikelets acute, nearly glabrous, about 4 mm. long. (Paspalus 

 Fliigge ; P. Elliottii Wats.) Low moist ground, Va. to Fla. and Tex. 



11. PANICUM L. PANIC GRASS 



Spikelets 1-flowered or rarely with a staminate flower below the terminal 

 perfect one, in panicles, rarely in racemes ; glumes very unequal, the first often 

 minute, the second subequal to the sterile lemma which often incloses a hyaline 

 palea and rarely a staminate flower ; fertile lemma and palea chartaceous-iu- 

 durated, nerves obsolete, the margins of the lemma inrolled ; grain free within 

 the rigid firmly closed lemma and palea. Annuals or perennials of various 

 habit. (An ancient Latin name of the Italian millet, Setaria italica, of uncer- 

 tain origin and meaning. ) 



a. Annuals b. 



b. Spikelets tuberculate 2. P. verrucosum. 



b. Spikelets smooth c. 



c. Plants glabrous , 8. P. dichotomiflorum. 



c. Plants more or less hispid d. CAHILLARIA. 

 d. Panicle erect, spikelets not over 8.5 mm. long e 

 e. Panicle more than half the length of the entire plant. 



Panicle diffuse ; spikelets 2-2.5 mm. long . . . . 3. P. c<ij>iJl<tr< . 

 Panicle narrow ; spikelets 8-3.5 mm. long . . . . 5. P. -ft. 

 e. Panicle not over one third the length of the entire plant. 



Culms stout; blades about 1 cm . wide 4. /'. (;<ttlinij<>ri. 



Culms delicate ; blades not over 6 mm. wide . . .6. P. pkilade&pMcwn. 



d. Panicle drooping ; spikelets 5 mm. long 7. P. milia<-< nm. 



a. Perennials /. 



/. Spikelets short- pediceled along one side of a rhachis forming spike- 

 like racemes 1. P. hemitomum. 



f. Spikelets in panicles g. 



g. Basal leaves similar to culm-leaves, not forming a winter ro- 

 sette ; culms simple or sometimes producing panicles from the 1 

 upper nodes h. 

 h. Spikelets long-pediceled. VIRGATA. 



Branches of panicle spreading 11. P. rif(/titni. 



Branches of panicle ascendim:. 



Spikelets 4.5 nun. long : leaves crowded at base of culm . 9. P. amnruin. 

 Spikelets 6 mm. long ; leaves not crowded at base of culm 10. P. aimit 

 h. Spikelets short- pedice led along the main branches of the pan- 



iele /. - Aiillosloflil A. 



*. Ilootstocks [in-sent 16. P. anceps. 



i. Rootatooki absent ; plants compressed at the leafy base. 



Kruit Mipitate ; spikelets conspicuously -eciind . . .14. /'. *tij>i/i/fnnt. 

 Fruit not stipitate ; Bpikeleto not OODBptauouftly secund. 

 Spikelets _' nun. long, crowded ; ;i few long hairs on the 



pedicels 13. /'. ni/rnxfnntes. 



Spikeleis _'.:>-:; nun. long ; no hairs on the pedicels. 



P.-micl.-s f.-\v (lowered, branches spreading . . .12. /'. l<m(fol i nt. 

 Panlolea densely (lowered, branches erect . . .15. P. conil'cunutn. 

 g. Banal leaves usually distinctly different from the culm-leaves, 

 forming' a winter rosette ; culms simple in spring but usually 

 much branched later in tin- season ; secondary paniele> smaller, 

 le-v i-.\M-ried than the [irimary ). DirnoTOMA. 

 '/. |.ike!ets :; nun. or more loiiiT "X". 



k. Leaves linear elongated, not i.ver "i mm. wide ; secondary pan- 

 icles :it the base only. 



Spikelets pointed jf. P. depnnptrntum. 



Spikelets blunt 18. p. IH .,-/,*// ,/HIH. 



