62 POACEAE 



3. Andropogon Virginicus L. Stems tufted, 5-10 dm. tall, the brandies in l's-3's : 

 leaf-slieatlis, at least the lower ones, more or less tuberculate-hirsute on the margins with 

 long usually lax hairs ; blades 4 dm. long or less, 2-5 mm. wide, rough or roughish, hirsute 

 on the upper surface near the base : spathes 3-5 cm. long, extending lieyond tlie racemes : 

 racemes generally in pairs, rarely in 3's or 4's, 2-3 cm. long: sessile spikelet 3-4 mm. 

 long, twice to i again as long as the internode, the awn straight, 10-15 mm. long ; pedi- 

 cellate spikelet wanting, or i-arely present as a minute scale, the pedicel exceeding the 

 sessile spikelet. 



In dry or moist soil, Massachusetts to Pennsylvania, Illinois, Florida and Texas. Fall. 



4. Andropogon longib^rbis Hack. Stems tufted, 5-10 dm. tall, the branches in 

 1'8-3's : leaf-sheatlis, especially those on the innovations, appressed-hirsute, shorter than 

 the internodes ; blades 5 dm. long or less, 7 mm. wide or less, those on the innovations 

 densely appreased-hirsute, those on the .stem more or less so beneath, rough above : spathes 

 3-5 cm. long, usually considerably exceeding the racemes, commonly brown : racemes in 

 pairs, 3-4 cm. long, stout: sessile spikelet 4-4.5 mm. long, about twice as long as the 

 rather stout rachis-internode, the awn straight or nearly so, 12-16 mm. long ; pedicellate 

 spikelet a subulate scale, or wanting, the pedicel rather stout and a little exceeding the 

 sessile spikelet. 



In dry pine lands, eastern and peninsular Florida. Spring and summer. 



5. Andropogon Tracyi Nash. Stems 5-8 dm. tall, the branches in I's or 2' s : leaf- 

 sheaths smooth and glabrous ; blades 2 dm. long or less, 1-2.5 mm. wide, smooth beneath, 

 rough above and hirsute toward the base : spathes 4-5 cm. long, rather broad, from slightly 

 shorter to exceeding the racemes : racemes in pairs, 3-4 cm. long, rather stout : sessile 

 spikelet 5 mm. long, about twice as long as the stout internode which is densely clothed 

 with silvery white hairs a little more than li times as long as the spikelet, the awn 1.5-2 

 cm. long, sometimes a little spiral at the base ; pedicellate spikelet wanting, or present as a 

 minute rudimentary scale, the pedicel exceeding the sessile spikelet. 



In dry soil, Alabama and Mississippi. Fall. 



6. Andropogon capillipes Nash. Smooth and glabrous, glaucous. Stems 8-12 dm. 

 tall : leaf-sheaths on the branches and summit of the stem much narrower than the 

 spathes, shorter than the peduncles which are usually in 3's and around which the sheaths 

 are tightly enrolled, the peduncles usually manifestly exserted ; blades 2 dm. long or less, 

 1-2.5 mm. wide, erect : spathes 2-3 cm. long, exceeding the racemes : racemes 1.5-2 cm. 

 long : sessile spikelet 3-3.5 mm. long, about twice as long as the internode, the awn 

 straight, 11-13 mm. long : pedicellate spikelet wanting, or present as a minute rudimen- 

 tary scale, the pedicel as long as or a little exceeding the sessile spikelet. 



In dry soil, North Carolina to Florida. Fall. 



7. Andropogon perangustatus Nash. Smooth and glabrous, the basal leaves nar- 

 row and flexuous, about k as long as the plant. Stems 2-8 dm. tall, slender, the branches 

 usually single, sometimes in pairs : leaf-blades 3 dm. long or less, 1-2 mm. wide : spathes 

 4-5 cm. long, extending beyond the summit of the racemes which are in pairs, 2.5-4 cm. 

 long : sessile spikelet 3.5-4 mm. Iqng, twice to J again as long as the internode, the awn 

 12-18 mm. long ; pedicellate spikelet wanting or rarely present as a minute scale, the ped- 

 icel exceeding the sessile spikelet. [A. Virginicus var. stenophyllus Hack., not A. stenophyl- 

 /«sE. &S.] 



In dry soil, Florida to Mississippi. Fall. 



8. Andropogon glaucopsls (Ell.) Nash. Glaucous, grayish green. Stems 6-10 

 dm. tall, rigid, rather stout, the branches in l's-2's, usually considerably above the middle : 

 leaf-sheaths smooth and glabrous, keeled, the lower ones compressed ; blades erect, 2 dm. 

 long or less, 2.5-6 mm. wide, smooth and glabrous beneath, roughened above with a 

 minute pubescence, the basal ones from ^-i as long as the stems : spathes 4-6 cm. long, 

 equallingor usually a little exceeding the racemes : racemes in pairs, 3-4.5 cm. long : sessile 

 spikelet 4.5-5 mm. long, long-acuminate, from equalling to nearly twice as long as the inter- 

 node, the awn 1.5-2 cm. long, straight ; pedicellate spikelet wanting, or present as a 

 rudimentary scale, the pedicel exceeding the sessile spikelet. [A. macrourus var. glaucop- 

 sis Ell.] 



In dry soil. North Carolina to Florida and Mississippi. Fall. 



9. Andropogon tetrastdchyus Ell. Stems tufted, 8-15 dm. tall : leaf-sheaths 

 densely villous, at least tlie lower ones, with dark hairs ; blades 4 dm. long or less, 2-4 

 mm. wide, the lower ones villous on both surfaces toward the base : spathes 3-4, rarely 6, 

 cm. long, extending beyond the racemes : racemes usually in 4's, sometimes fewer, 3-4 

 cm. long : sessile spikelet 3-4 mm. long, twice to I again as long as the internode, the 

 awn straight, 1.5-2 cm. long ; pedicellate spikelet wanting, or rarely present as a minute 



