POACEAE 



1. Coleanthus subtilis (Tratt.) Seidi. 

 Aloss-grass. Fig'. 315. 



Schmidtia snbtilis Tratt. Fl. Austr. 1: 12. 1816. 



Coleanthus subtilis Seidel; Roem. & Schult. Syst. Veg. 2: 276. 1S17. 



Culms tufted, mostly 1-3 cm. tall ; panicles terminal and 

 ixillar}-; sheaths inflated; spikelets about 1 mm. long. 



In mud along the lower Columbia River. October. Type locality, 

 ^ European. 



24. SPOROBOLUS R. Br. Prodr. Fl. Nov. HoU. 169. 1810. 



Spikelets 1 -flowered, the rachilla disarticulating above the glumes, not produced beyond 

 the palea ; glumes usually unequal, the second often as long as the spikelet ; lemma 

 membranaceous, awnless ; palea usually prominent and as long as the lemma or longer; 

 seed free from the pericarp. Annual or perennial grasses with small spikelets in open or 

 contracted panicles. [Greek, seed-throwing.] 



Species about 95 in the warm regions of both hemispheres. Type species, Agrostis indica L. 

 Plants annual. 



Panicles spike-like, often inclosed in the sheaths. 

 Panicles diffuse, the pedicels capillary. 

 Plants nerennial. ■ , ,-a- 



Plants producing creeping rhizomes; blades short, flat; panicle diffuse. 

 Plants without rhizomes. 



Second glume about half as long as the spikelet, the first a little shorter; spikelets 5-6 mm. long. 



4. S. asper. 

 Second glume as long as the spikelet, the first glume shorter. 



Panicles diffuse, the pedicels capillary. 5. 5'. airoidcs. 



Panicles contracted, open or spikelike, the pedicels short. 



Panicles, or the exserted portion, somewhat open, the branches naked below. 



6. S. cryptandrus. 

 Panicles spikelike, the branches floriferous from the base. 7. 6". contractus. 



1. 5". neglectits. 



2. S. confusus. 



3. 5'. asperifolius. 



1. Sporobolus neglectus Nash. 

 Small Rush-grass. Fig. 316. 



sporobolus neglectus 'l<:ash. Bull. Torrey Club 22: 464. 1895. 

 Sporobolus '■aginacfior-us neglectus Scribn. U. S. Dept. Agr. Div. 

 Agrost. Bull. 17: ed. 2. 170. /. 466. 1901. 



Annual ; culms spreading or erect, 10-30 cm. tall, 

 smooth ; sheaths smooth, often inflated ; ligule a very 

 short ciliate ring; blades flat, glabrous, scabrous on the 

 margin, 2-8 cm. long, 1-2 mm. wide ; panicles spike- 

 like. 2-3 cm. long, scattered along the stem, partially 

 or wholly concealed in the sheaths ; spikelets about 2 

 mm. long; glumes and lemma nearly equal. 



Open sterile ground, eastern Washington to MassachusC-ts 

 and Tennessee. Tulv. Type locality: northeastern United 

 States. 







iA 





2. Sporobolus confusus Vasey. 

 Tufted Annual Dropseed. Fig. 317. 



sporobolus confusus Vasey, Bull. Torrey Club 15: 293. 1888. 



.A^nnual ; culms slender, 15-20 cm. tall, often 

 depauperate ; blades mostly less than 3 cm. long ; 

 panicles oblong, dift'use, often more than half the 

 length of the entire plant, the branches capillary, 

 spreading. 2.5-3.5 cm. long; spikelets 1-1.5 mm. 

 long, the glumes about half as long, subequal, obtuse, 

 sparsely pilose. 



Open sandy or gravelly, usually moist ground, mostly near 

 streams or lakes in the mountains. Upper Sonoran Zone; 

 Washington and Montana and to Texas and ^Mexico. July- 

 Sept. Type locality: Mexico. 



