Figure 1151. — Andropogon rhizomatus, X 1. (Type.) 



MANUAL OF THE GRASSES OF THE UNITED STATES 



Sandy ground along the Gulf coast, 

 western Florida, Mississippi (Horn 

 Island), and Louisiana (Last Island). 



12. Andropogon rhizomatus Swal- 

 len. (Fig. 1151.) Culms 50 to 70 em. 

 tall, scattered or in small dense tufts, 

 erect from short rhizomes, sparingly- 

 branching above the middle; sheaths 

 rounded or obscurely keeled, much 

 longer than the internodes; blades 10 

 to 25 cm. long, 1 to 3 mm. wide, flat or 

 loosely involute, glabrous; raceme 2 to 

 3 cm. long, strongly flexuous, partly 

 enclosed or exserted from the very in- 

 conspicuous spathe; peduncles 3 to 7 

 cm. long; sessile spikelet 5 to 6 mm. 

 long, the first glume rounded on the 

 back, obscurely keeled near the sum- 

 mit; awn 8 to 10 mm. long, geniculate, 

 twisted . below the bend; pedicellate 

 spikelet 2 to 3 mm. long. % — 

 Rocky ground, southern Florida. 



13. Andropogon stoSonifer (Nash) 

 Hitchc. (Fig. 1152.) Resembling A. 

 scoparius; culms as much as 1.5 m. 

 tall, solitary or few in a tuft, with 

 slender, creeping scaly rhizomes; foli- 

 age glabrous to villous, the blades flat, 

 as much as 5 mm. wide; racemes 3 to 4 

 cm. long, the slender rachis joints and 

 pedicels silky villous; first glume of 

 both sessile and pedicellate spikelets 

 sometimes bifid at apex; sessile spike- 

 let 5 to 7 mm. long, scabrous, especi- 

 ally toward the summit and on the 

 margins. % {Schizachyrium tri- 

 aristatum Nash.) — Sandy woods, 

 southern Georgia, Florida, and Ala- 

 bama. 



Section 2. Artheolophis Trin. 



Branching perennials; racemes 2 to 

 few on each peduncle; rachis 

 joints slender, mostly pubescent; 

 sessile spikelet awned. 



14. Andropogon gerardi Vitman. 

 Big bluestem. (Fig. 1153.) Plants 

 often glaucous; culms robust, often 

 in large tufts, sometimes with short 

 rhizomes, 1 to 2 m. tall, usually 

 sparingly branching toward the sum- 

 mit; lower sheaths and blades some- 

 times villous, occasionally densely so, 

 the blades flat, elongate, mostly 5 to 



757 



Figure 1152. — Andropogon stolonifer, X 1. (Fred- 

 holm, 6122 Fla.) 



10 mm. wide, the margins very sca- 

 brous; racemes on the long-exserted 

 terminal peduncle mostly 3 to 6, 

 fewer on the branches, 5 to 10 cm. 

 long, usually purplish, sometimes 

 yellowish; rachis straight, the joints 

 and pedicels stiffly ciliate on one or 

 both margins, the joints hispid at 

 base; sessile spikelet 7 to 10 mm. 

 long, the first glume slightly sulcate, 

 usually scabrous, the awn geniculate 

 and tightly twisted below, 1 to 2 

 cm. long; pedicellate spikelet not 



