496 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



101. GYMNOPOGON Beauv. 



Figure 1053.— Distribution of 

 Ctenium aromaticum. 



Spikelets 1- or rarely 2- or 3-flowered, nearly sessile, appressed and 

 usually remote in two rows along one side of a slender continuous 

 rachis, the rachilla disarticulating above the glumes and prolonged 

 behind the one or more fertile florets as a 

 slender stipe, bearing a rudiment of a floret, 

 this sometimes with 1 or 2 slender awns ; glumes 

 narrow, acuminate, 1-nerved, usually longer than 

 the floret; lemmas narrow, 3-nerved, the lateral 

 nerves near the margin, the apex minutely 

 bifid, bearing between the teeth a slender awn, 

 rarely awnless. Perennials or rarely annuals 

 (ours perennial), with short, stiff, flat blades, 

 often folded in drying, numerous long slender divergent or reflexed 

 spikes, approximate on a slender stiff axis. Type species, Gymnopo- 

 gon racemosus Beauv. (G. am- 

 biguus). Name from Greek 

 gumnos, naked, and pogon, 

 beard, alluding to the naked 

 prolongation of the rachilla. 

 Awn longer than the lemma 



1. G. AMBIGUUS. 



Awn shorter than the lemma or none. 

 Spikes subcapillary, naked for 1 

 to several cm at base; spikelets 

 1 -flowered. 



2. G. BREVIFOLIUS. 



Spikes stouter, floriferous from 

 base; spikelets 2- or 3-flowered, 

 the rachilla zigzag 



3. G. CHAPMANIANUS. 



1. Gymnopogon ambiguus 



(Michx.) B. S. P. (Fig. 1055.) 

 Culms 30 to 60 cm tall in 

 small clumps with short scaly 

 rhizomes, suberect to spread- 

 ing, rigid, sparingly branching; 

 leaves numerous, approximate 

 with overlapping sheaths, or 

 the lower rather distant; 

 blades spreading, 5 to 15 mm, 

 mostly about 10 mm wide, the 

 base rounded-truncate ; spikes 

 10 to 20 cm long, floriferous from base, the lower spikelets often 

 remote; glumes 4 to 6 mm long; lemma with an awn 4 to 6 mm long, 

 the rudiment bearing a delicate shorter awn. % — Dry pinelands, 

 Coastal Plain, New Jersey to Florida and Texas ; dry woods, Tennessee 

 to Kansas and south (fig. 1056). 



2. Gymnopogon brevifolius Trin. (Fig. 1057.) Differing from 

 G. ambiguus in the longer, more slender, somewhat straggling culms, 



Figure 1054.— Ctenium fforidanum. Plant, X 1; glumes 

 and florets, X 5. (Combs 702a, Fla.) 



