GRAMINEAE. 105 



attenuate into a long slender involute tip, smooth and glabrous beneath, scabrous 

 above, or somewhat hairy at the base; panicle 5-12.5 cm. in length, linear, strict, 

 its branches 2.5-5 cm - l° n g> appressed ; spikelets 6-8 mm. long, the outer scales 

 unequal, acute ; third scale pubescent at the base, much longer than the second 

 and greatly exceeded by the long-acuminate almost awned palet. In dry soil, 

 Del. to 111., south to Fla. and Tex. Aug. -Sept. 



2. Sporoboius longifolius (Torr. ) Wood. Long-leaved Rush-grass. 

 (I. F. f. 34.2.) Culms 4.5-10 dm. tall, erect, occasionally branched. Leaves 1- 

 4.5 dm. long, 2-4 mm. wide at the base, attenuate into a long slender involute tip, 

 smooth and glabrous beneath, scabrous and hairy at the base above; panicle more 

 or less included in the upper sheath, 7.5-25 cm. in length, linear, strict, the 

 branches 2.5-5 cm - l° n &> erect ; spikelets 4-5 mm. long ; outer scales unequal, 

 acutish, glabrous, the lower shorter; third scale glabrous, acutish or obtuse, exceed- 

 ing the second and equalling or a little shorter than the obtuse palet. In dry soil, 

 Me. to Penn., Neb. and Kans., south to Fla. and Tex. Aug. -Sept. 



3. Sporoboius pilosus Vasey. Hairy Rush-grass. (I. F. f. 343.) Culms 

 3-4.5 dm. tall, erect, rigid, stout. Leaves 7.5-15 cm. long, 2-4 mm. wide at base, 

 erect, rigid, attenuate into a slender involute tip, the lower papillose-hirsute on 

 both sides, the upper usually glabrous beneath, scabrous above and somewhat hairy 

 near the base; panicle 5-7.5 cm. in length, included at the base, erect, strict, its 

 branches 1.25-2.5 cm. long, erect; spikelets 5 mm. long, the outer scales unequal, 

 glabrous, obtuse, the lower shorter; third scale obtuse, glabrous, somewhat exceed- 

 ing the second and equalling or a little longer than the obtuse palet. In dry soil, 

 Kans. and Mo. Aug. -Sept. 



4. Sporoboius vaginaefldrus (Torr.) Wood. Sheathed Rush-grass. 

 (I. F. f. 344.) Culms 2-4.5 dm. tall, erect, slender. Sheaths usually inflated; 

 leaves 2 mm. wide or less, smooth and glabrous beneath, scabrous and hairy near 

 the base above, attenuate into a slender involute point, the lower elongated, the up- 

 per 2.5-7.5 cm. long, setaceous; panicles 1. 8-5 cm. in length, the terminal one ex - 

 serted or sometimes partially included, strict, the branches 1.25 cm. long or less, 

 erect, the lateral ones enclosed in the sheaths; spikelets 3.5-4.5 mm. long, the outer 

 scales unequal, acuminate, the third scale scabrous, sparingly appressed-pubescent, 

 about as long as the second and equalling or slightly exceeded by the very acute 

 palet. In dry soil, N. H. to N. Y., 111. and Neb., south to Ga. and Tex. Aug.- 

 Sept. 



5. Sporoboius neglectus Nash. Small Rush-grass. (I. F. f. 345.) Culms 

 1.5-3 dm. tall, erect from a usually decumbent base, slender. Sheaths inflated; 

 leaves 2 mm. wide or less at the base, smooth and glabrous beneath, scabrous and 

 hairy near the base above, attenuate into a slender point, the lower elongated, the 

 upper 2.5-7.5 cm. long, setaceous; terminal panicle 2.5-6.25 cm. in length, usually 

 more or less included in the upper sheath, strict; lateral panicles enclosed in the 

 sheaths; spikelets about 3 mm. long, the outer scales acute, the third scale acute, 

 glabrous, a little longer than the second and about equalling the acute palet. In 

 dry soil. Mass. to Ky., Neb. and Kans. Aug. -Sept. 



6. Sporoboius brevifolius (Nutt) Nash. Short - leaved Rush -grass. 

 I. F. f. 346.) Smooth and glabrous; culms 1.5-4.5 dm. tall, arising from a hori- 

 zontal rootstock, erect, slender, decumbent and branching at the base. Leaves 

 1.25-5 cm. long, involute-setaceous; panicle 1.25-7.5 cm. in length, usually about 

 3.75 cm., linear, its branches 6-12 mm. long, erect or appressed; spikelets 2.5-3 

 mm. long, the outer scales unequal, less than half as long as the third, obtuse or 

 abruptly acute, scabrous on the keel and at the apex; third scale long-acuminate, 

 sometimes cuspidate, scabrous toward the apex. Anticosti Isl. and Me. to Br. Col., 

 south in the mountains to N. Mex. and Cal. Summer. 



7. Sporoboius cuspidatus (Torr.) Wood. Prairie Rush-grass. (I. F. f. 

 347.) Smooth and glabrous; culms 3-6 dm. tall, erect, simple or somewhat 

 branched. Leaves 2.5-10 cm. long, less than 2 mm. wide at the base, erect, in- 

 volute-setaceous, at least when dry; panicle 3.75-12.5 cm. in length, slender, its 

 branches 6-25 mm. long, appressed; spikelets 2.5-3 mm. long, the outer scales half 

 to three-quarters as long, acuminate or cuspidate, scabrous on the keel; third scale 

 k>ng-acumin;tte and cuspidate, sparingly scabrous. In dry soil, Manitoba to the N. 

 W. Terr., south to Mo. and Kans. Aug. -Sept. 



