198 



GRAMINEAE. 



VOL. I. 



ii. Sporobolus uniflorus Muhl. Late-flowering Dropseed. Fig. 474. 



Poa itniflora Muhl. Descr. Gram. 151. 1817. 

 Agrostis serotina Torr. Fl. U. S. i : 88. 1824. 

 Sporobolus serotinus A. Gray, Man. 577. 1848. 

 S. uniflorus Muhl. ; Scribn. & Merr. Circ. U. S. Dep. Agr. 

 Agrost. 27: 5. 1900. 



Glabrous and smooth or very nearly so, culms 6'-i8' 

 tall, from an annual root, erect, slender, simple. 

 Sheaths short, confined to the lower part of the culm ; 

 ligule less than i" in length, irregularly truncate; 

 blades ->" wide or less, slightly scabrous above, flat, 

 the basal one-third to half the length of the culm, 

 those of the culm 2'-^' long; panicle 3 '-9' in length, 

 the branches capillary, erect or ascending, the lower 

 \'-2\' long; spikelets about " long, the outer scales 

 subequal, obtuse, smooth or sometimes sparingly sca- 

 brous; third scale twice the length of the outer ones, 

 acuminate. 



In wet sandy soil, Maine to Ontario and Michigan, south 

 to New Jersey. Sept.-Oct. 



12 Sporobolus argutus (Nees) Kunth. Pointed Dropseed-grass. Fig. 475. 



Vilfa arguta Nees, Agrost. Bras. 2: 395. 1829. 

 Sporobolus argiitus Kunth, Enum. i : 215. 1833. 



Culms i tall or less, erect, or somewhat decumbent 

 at the base, simple or sometimes branched, smooth and 

 glabrous. Sheaths shorter than the internodes, their 

 margins sometimes hirsute at the top; ligule a ring of 

 short hairs; blades i'-2' long, i"-2" wide at the base, 

 acuminate, smooth and glabrous beneath, scabrous and 

 often sparingly hairy at the base above; panicle ii'-3' 

 in length, the branches i'-i' long, verticillate, at first 

 appressed, finally widely spreading; spikelets I" long; 

 outer scales smooth and glabrous, the first rounded or 

 obtuse, one-quarter the length of the acute second one; 

 third scale about equalling the second, acute. 



In sandy and rocky places, Kansas and Colorado, south 

 to Texas and Mexico. Also in the West Indies. July-Sept. 



13. Sporobolus gracilis (Trin.) Merrill. Purple Dropseed-grass. Wire-grass. 



Fig. 476. 



Agrostis juncea Michx. Fl. Bor. Am. i : 52. 1803. Not 



Lam. 1783. 

 Vilfa gracilis Trin. Mem. Acad. St. Petersb. VI. 5- : 74. 



1840. 



Sporobolus jnnceus Kunth, Rev. Gram, i : 68. 1829. 

 S. ejuncidus Nash, in Britt. Man. 106. 1901. 

 5". gracilis Merrill, Rhodora, 4: 48. 1902. 



Glabrous and smooth throughout, culms i-2 tall, 

 tufted, erect, slender, simple. Sheaths shorter than the 

 internodes; ligule very short; blades filiform or seta- 

 ceous, the basal 6'-i long, numerous, those of the culm 

 few, i '-3' long; panicle 3'-7' in length, open, the 

 branches verticillate, the lower i'-2' long, widely spread- 

 ing; spikelets ii"-i", purple, the outer scales very- 

 unequal, the first obtuse or acutish, one-fourth to one- 

 third the length of the acute second one ; third scale 

 subacute or blunt, equalling the second and the obtuse 

 palet. 



Dry sandy soil, Virginia to Florida, west to Texas. 

 Rush-grass. Aug.-Sept. 



