58 POACEAE 



the outermost one larger than the rest, membranous, exhaling a balsam-odor when fresh 

 or when soaked in water, second scale shorter, thinner, somewhat rigid, acute, the third 

 scale empty, or rarely in the sessile spikelets infolding a staminate flower, the fourth scale 

 very thinly hyaline, in the sessile spikelets enclosing a perfect flower, in the pedicellate 

 spikelets either empty or enclosing a staminate flower ; palet minute or wanting. Stamens 

 3. Styles distinct. Stigmas plumose. 



1. Elionurus tripsacoides H. & B. Stems 6-15 dm. tall, from a rootstock, branched 

 above : leaf-blades 5 dm. long or less, involute above the base when dry and about 0.8 

 mm. in diameter, 3-5 mm. wide at the base, hirsute above near the base : racemes finally 

 exserted, 7-14 cm. long, the rachis-internodes pilose excepting the inner surface : sessile 

 spikelet 6.5-8 mm. long, about twice as long as the rachis-internode ; pedicellate spikelet 

 5-6 mm. long, reaching or extending a little beyond the apex of the sessile spikelet, the 

 pedicel pilose, excepting the inner surface. 



In low pine lands, Florida to Texas. Also in Mexico and South America. Summer and fall. 



8. SCHIZACHYRIUM Nees. 



Annual or perennial grasses, tufted, or from rootstocks, with flat or involute leaf -blades, 

 and spike-like racemes, singly disposed, terminating the stem or its branches. Spikelets 

 in pairs at each node of the articulated and frequently hairy rachis, one sessile, the other 

 pedicellate. Sessile spikelet of 4 scales, the outer 2 indurated, sometimes pubescent, the 

 remainder of the scales hyaline, the fourth scale entire or 2-ioothed at the apex, bearing a 

 straight, contorted or spiral awn ; palet small, hyaline. Pedicellate spikelet sterile, of 1 

 or 2 scales, or wanting. Stamens 1-3. Styles distinct. Stigmas plumose. BEARD GRASS. 

 Internodes of the racemes glabrous, or merely shortly appressed-pubescent on 



the back, the racemes hence appearing naked. 

 Internodes as well as the first scale of the sessile spikelet glabrous. 



Sessile spikelet 5-6 mm. long ; pedicel stout, oblong-elliptic, the outer mar- 

 gin ciliate its entire length. 1. S. semibcrbe. 

 Sessile spikelet 4 mm. long ; pedicel slender, linear, the outer margin ciliate 



only at the apex. 2. S. tenerum. 



Internodes as well as the first scale of the sessile spikelet appressed-pubes- 

 cent. 3. S. oligostachyum. 

 Internodes of the racemes and the pedicels long-ciliate on the margins, the in- 

 ner or usually both surfaces glabrous, the racemes hence appearing hairy. 

 Leaf-blades fiat and broad ; rachis-internodes and pedicels glabrous on the 

 back, or the former rarely sparsely pilose at the summit, the marginal 

 hairs much shorter than the respective organs. 

 Stems tufted, no stolons. 

 . Sheaths and leaf -blades glabrous or sometimes sparingly pubescent. 



Spikelets 5-7 mm. long. 4. S. scoparium. 



Spikelets 10 mm. long. 5. S. acuminatum. 



Sheaths and leaf-blades densely long-villous. 6. S. viUosissimum. 



Stems not tufted, stoloniferous, rootstocks long and slender. 



Pedicellate spikelet staminate : lower sheaths numerous, crowded, the 



blades spreading. 7. S. maritimum. 



Pedicellate spikelet sterile : lower sheaths few, not crowded, the blades 



erect. 



Sessile spikelet 6-7 mm. long, the first scale strongly tuberculate- 

 roughened ; pedicellate spikelet of a single scale, about 3 mm. 

 long, single-awned. 8. S. stoloniferum. 



Sessile spikelet 9-10 mm. long, the first scale smooth or nearly so ; 

 pedicellate spikelet of 2 scales, 6-8 mm. long, the first scale 3- 

 awned. 9. S. triaristatum. 



Leaf-blades involute, filiform ; rachis-internodes and pedicels strongly pilose 

 on the back, the marginal and dorsal hairs much longer than the re- 

 spective members. 10. S. gracile. 



1. Schizachyrium semib6rbe Nees. Smooth and glabrous. Stems tufted, 6-12 dm. 

 tall, the branches in 1's or 2's : leaf -blades 3 dm. long or less, 2-5 mm. wide : racemes 

 single, 5-8 cm. long, partially included at the base, the rachis-internodes with a dense 

 ring of short hairs at the base, thick, channeled on the inner surface : sessile spikelet 5-6 

 mm. long, the first scale rounded on the back, roughened, acuminate, the awn of the fourth 

 scale 12-15 mm. long, geniculate, tightly spiral at the base, the column exserted ; pedicel- 

 late spikelet consisting of a single hispidulous scale about 3 mm. long with an equally long 

 awn, the pedicel stout, oblong-elliptic, ciliate on the outer margin, shorter than the inter- 

 node. [Andropogon semiberbis (Nees) Kunth.] 



In dry rocky or sandy ground, southern peninsular Florida. Also tropical America. Summer. 



2. Schizachyrium tenerum Nees. Smooth and glabrous. Stems tufted, slender, 

 often weak and decumbent, 4-10 dm. long, the branches in 1's or 2's : leaf -blades 2 dm. 

 long or less, 0.5-2 mm. wide, the lower ones often sparingly hirsute above near the base : 

 racemes single, 3-6 cm. long, the rachis-internodes with a ring of hairs at the base, stout, 



