GRASSES OF IOWA. 



21 



TKIPSACUM DACTYLOIDES. 



DESCRIPTION. 



Gam a Grass. Spikelets monoecious, in jointed unilateral spikes, 

 staminate above, and fertile below. Staminate spikelets in pairs, 

 sessile at each triangular joint of the narrow rachis, both alike, two- 

 flowered, longer than the 

 joints; glumes 4, coriaceous, ^ ■ I 

 the lower (outer) one-nerved, j . 1/ / 



the second boat-shaped, the 

 upper with the palets very 

 thin and membranaceous, awn 

 less; anthers opening by two 

 pores at the apex. Pistillate 

 spikelets two-flowered (the 

 lower flower neutral) single 

 and deeply imbedded in each 

 oblong joint of the cartilagi- 

 nous thickened rachis, occupy- 

 ing a boat-shaped recess which 

 is closed by the polished and 

 cartilaginous, ovate outer 

 glume, the inner glume much 

 thinner and pointed, the up- 

 per with the palets very thin 

 and scarious, pointless. Styles 

 united ; stigmas very long 

 (purple), hispid. Grain ovoid, 

 free. Culms stout and tall, 

 solid, from very thick, creep- 

 ing rootstalks. Leaves broad 

 and flat. Spike axillary and 

 terminal, separating spontane- 

 ously into joints at maturity. 



, -»j , , „ . , Fig 14. Tripsacum daclyloides L. Gama grass. 



^IName irom the (jreek word a< Tw0 joints of the pistillate portion of the spike ; 



for to rub, perhaps in allusion b > a pistillate spikelet; c, outer glume of the same; 



, .. , . e, flowering glume and palea s-howing the long 



to the polished fertile spike.) exserted stigmas;/, staminate spikelet. 



DISTRIBUTION. 



Iowa. Appanoose County, Decatur County (Fitzpatrick) ; Mus- 

 catine (Reppert) ; Decatur County, Van Wert (Hitchcock). 



