POACEAE 63 



scale, the pedicel considerably exceeding the sessile spikelet. \_A. Virginicus var. tetra- 

 stachyus (Ell.) Hack.] 



In dry or moist soil, South Carolina to Florida and Alabama. Fall. 



10. Andropogon Mohrii Hack. Stems 8-12 dm. tall : leaf-sheaths densely ap- 

 pressed-hirsute ; blades 3 dm. long or less, 5 mm. wide or less, densely appressed-hirsute : 

 spathes 4-5 cm. long, equalling or a little shorter than the racemes : racemes in 4's, 3-4 

 cm. long, rather stout, the hairs at the summit of the rachis-internodes J again as long as 

 the spikelets : sessile spikelet about 4.5 mm. long, about twice as long as the internode, 

 the awn straight or nearly so, slightly if at all twisted at the base, 2-2.5 cm. long ; pedicel- 

 late spikelet wanting, or sometimes present as a small subulate scale, the pedicel usually a 

 little shorter than the sessile spikelet. 



In low pine lands, western Florida to Louisiana. Fall. 



11. Andropogon gracilior (Hack.) Nash. Stems tufted, slender, 3-7 dm. tall, 2-3 

 times as long as the basal leaves, the lower branches single : leaf -sheaths glabrous, shorter 

 than the internodes, the terminal ones more or less enlarged, 5-7 cm. long, 2-3 mm. wide ; 

 stem-leaves with blades 1.5 dm. long or less, 1-2 mm. wide, smooth beneath, rough above 

 and sparingly hirsute near the base : racemes in pairs, slender, about 3 cm. long, exserted, 

 or slightly included at the base : sessile spikelet 3.5-4 mm. long, equalling or somewhat 

 exceeding the internode, the awn geniculate, 1.3-2 cm. long, loosely spiral at the base, the 

 column exserted ; pedicellate spikelet a minute rudimentary scale, the pedicel usually about 

 again as long as the sessile spikelet. 



In dry or moist places, Florida to Alabama ; also in Tennessee. Fall. 



12. Andropogon Ellitfttii Chapm. Stems tufted, 5-8 dm. tall, rather stout, 2-3 

 times as long as the basal leaves : leaf -sheaths shorter than the internodes, the lower ones 

 and those of the innovations densely appressed-hirsute, those of the inflorescence much en- 

 larged and densely crowded at the summit and also sometimes at the nodes below, 8-11 cm. 

 long, 3-6 mm. wide ; blades 2 dm. long or less, 2-5 mm. wide, usually smooth beneath, 

 rough above and hirsute near the base : racemes in pairs, slender, 3-4 cm. long, the longer 

 one at each node exserted, the rest concealed in the spathes : sessile spikelet 4.5-5 mm. 

 long, equalling or somewhat exceeding the internode, the awn geniculate, 1.5-2.3 cm. long, 

 usually spiral at the base, the column much exserted ; pedicellate spikelet a minute rudi- 

 mentary scale, the pedicel usually about \ again as long as the sessile spikelet. 



In dry sandy soil, South Carolina and Tennessee to Florida and Mississippi. Fall. 



13. Andropogon campylorachens Nash. Stems densely tufted, 4-8 dm. tall, the 

 terminal internode much elongated and slender, the branches single : leaf-sheaths much 

 exceeding the internodes, overlapping, those on the stem 13-17 cm. long, sparingly hirsute, 

 those on the innovations densely hirsute with ascending hairs, the terminal one very nar- 

 row and tightly embracing the stem, the upper sheaths on some of the stems much en- 

 larged and producing smaller spathes in their axils with concealed racemes ; blades erect, 

 2 din. long or less, 2-3 mm. broad, smooth beneath, hirsute above near the base : racemes 

 in 2*8-4*8, flexuous, 5-10 cm. long: sessile spikelet 5 mm. long, usually much exceeded 

 by the internode, the terminal hairs of which are 8-10 mm. long, the awn more or less 

 contorted, 1.5-2 cm. long, barely if at all twisted at the base ; pedicellate spikelet wanting, 

 or present as a minute rudimentary scale, the pedicel much exceeding the sessile spikelet. 



In dry sandy soil, southern peninsular Florida and Mississippi. Fall. 



14. Andropogon brachystachyus Chapm. Stems tufted, 6-15 dm. tall, the 

 branches in l's-3's and usually pilose just below the nodes : leaf-sheaths smooth and 

 glabrous ; blades erect, 3 dm. long or less, 3-4 mm. wide, smooth beneath, on the upper 

 surface rough and hirsute near the base : racemes in pairs, shortly exserted, or partly in- 

 cluded at the base, 1-2 cm. long : sessile spikelet 3-4.5 mm. long, about twice as long as 

 the internode, the first scale pubescent between the keels, the awn of the fourth scale 

 straight or nearly so, 6-9 mm. long ; pedicellate spikelet consisting of a single scale, the 

 pedicel shorter than the sessile spikelet. 



In moist pine lands, Florida. Summer and fall. 



15. Andropogon Floridanus Scribn. Stems tufted, 5-16 dm. tall, the branches in 

 l's-3's : leaf -sheaths roughish, usually shorter than the internodes ; blades 5 dm. long or 

 less, 1 cm. wide or less, rough : racemes in pairs, occasionally in 3's or 4's, 3-4 cm. long, 

 exserted, or partly included at the base : sessile spikelet 3.5-4 mm. long, equalling or a little 

 longer than the internode, the awn straight, 8-12 mm. long ; pedicellate spikelet wanting 

 or present as a small scale, the pedicel exceeding the sessile spikelet. 



In dry pine lands, peninsular Florida. Summer and fall. 



16. Andropogon subt6nuis Nash. Stems 3-6 dm. tall, slender, the branches single : 

 leaf-sheaths smooth and glabrous ; blades 1.5 dm. long or less, 1-2 mm. wide, smooth 



