This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Aristida oligantha Michx. Fl. Bor. Am. 1: 41. 1803.
Glabrous, culms 1°-2° tall, erect, slender, dichot-omously branched, smooth or roughish. Sheaths exceeding the internodes, loose; ligule very short, minutely ciliate; blades 1'-6' long, 1/2"-1" wide, smooth, the larger ones attenuate into a long slender point; spikelets few, borne in a lax spike-like raceme or panicle; first scale 5-nerved, occasionally 7-nerved at base, acuminate or short-awned, equalling or somewhat shorter than the second, which bears an awn 2."-4" long; third scale shorter than the first, awns divergent or spreading, the middle one 1Y-2Y long, the lateral somewhat shorter.
Dry soil, New Jersey to Nebraska, and Texas. Aug.-Sept. Ant-rice.
Aristida gracilis Ell. Bot. S. C. & Ga. 1: 142. 1817.
Aristida gracilis var. depauperata A. Gray, Man. Ed. 5, 618. 1867.
Glabrous and smooth throughout, culms 6'-2° tall, erect, simple or branched. Sheaths shorter than the internodes; ligule very short; blades 1'-4' long, 1" wide or less, flat, or involute when, dry; panicle spike-like, 3'-7' long, slender; spikelets about 3" long; outer scales equal, or the lower somewhat shorter, awn-pointed; third scale about equalling the second, generally mottled, middle awn horizontal, the terminal straight portion 3"-7" in length, the lateral awns 1"-3" long, erect.
Dry soil. New Hampshire to Missouri, south to Florida and Texas. Aug.-Sept.
Culms slender, finally branching, 1°-2 1/2° tall; sheaths glabrous or sparsely hirsute; blades 2'-6' long, 1" wide or less, erect, involute; panicle 8'-16' long, slender, its branches appressed; spikelets 4"-5" long, the empty scales manifestly awned, about equal, the flowering scale strongly hispidulous above the middle, equalling or exceeding the empty scales, the awns spreading, the middle one 7"-13" long, the lateral ones shorter.
In sandy soil, Iowa and Kansas to Mississippi and Texas. Aug.-Oct.
Glabrous and smooth, culms 1°-2 1/2° tall, erect, simple or sparingly branched at the base. Sheaths longer than the internodes, crowded at the base of the culm; ligule very short; blades 4's' long, about 1" wide, flat, or becoming involute in drying, attenuate into a long point; spike-like panicles 5'-18' long, strict, or sometimes nodding, its branches appressed; outer scales of spikelet awn-pointed, the first longer than the second; the third scale from two-thirds to three-quarters as long as the first, middle awn 9"-12" long, horizontal, the lateral awns somewhat shorter, erect or divergent.
In dry soil, Massachusetts to Minnesota, south to Florida and Texas. Sept.-Oct.