10 POACEAE. 



4. SCHIZACHYRIUM Nees. Erect plants, tufted or from rootstocks, 



with spike-like racemes. Spikelets iu pairs at each node of the articulate and 



frequently hairy rachis. Sessile spikelet of 4 scales, the fourth scale entire or 



2-toothed, bearing a straight, contorted, or spiral awn. — Be.vrd-grass. 



Internodes of the racemes glabrous or nearly so, the racemes hence appearing naked. 



1. S. semiberbe. 

 Internodes of the racemes and pedicels long-ciliate. the racemes 



hence appearing hairy. 2. S. gracile. 



1. S. semiberbe Nees. Stems tufted, 6-12 dm. tall : racemes 5-8 cm. long, the 

 raehis-internodes with a dense ring of short hairs at the base, thick, channeled 

 on the inner surface: sessile spikelet with 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. — Everglades and pinelands. — 

 (Bah., Cuba, Ant.) 



2. S. gracile (Spreng.) Xash. Stems densely tufted, slender, 3-6 dm. tall: 

 racemes 3-5 cm. long, silvery-white: sessile spikelet 5-6 mm. long, the awn 

 geniculate, 13-20 mm. long, tightly spiral to the bend, loosely so above, the 

 column much exserted. — Pinelands. — (Bah., Cuba, Ant.) 



5. ANDROPOGON [Royen] L. Erect plants with spike-like racemes, 

 which often j)rotrude from the side of a membranous spathe-like sheath. 

 Sessile spikelet of 4 scales, bearing a straight contorted or spiral awn, or some- 

 times awnless. Pedicellate spikelet usually sterile, of 1 or 2 scales, some- 

 times of 4 scales and enclosing a staminate or more rarely a perfect flower, or 

 frequently entirely wanting. — Broom-grass. Beard-grass. Sand-grass. 



Inforescence oblong to oval or obovate, the branches many times divided, the lower 

 ones elongated, forming 1 or more corymbiform masses ; upper stem-leaves usually 

 equalling or exceeding the inflorescence. 1. A. tenuispathcus. 



Inflorescence long and narrow, commonly linear, the branches 

 not much divided nor the lower ones excessively elon- 

 gated, hence forming no corymbiform masses ; upper 

 stem-leaves usually sliorter than the inflorescence. 

 Sheaths and spathes not enlarged. 



I'airs of racemes sessile or nearly so. the common 



peduncle not exceeding .5 mm. in length. 2. A. loiu/ibcrbis. 



Pairs of racemes never sessile, the common peduncle 

 over 5 mm. in length, usually exceeding 1 cm. or 

 sometimes much exserted. 

 Stem slender, sparingly branched : leaf-blades 3 



mm. wide or less: awns 1..5-2 cm. long. .3. A. Tracyi. 



Stem stout, much branched above : leaf-blades 4-7 



mm. wide: awns C-10 mm. long. 4. A. Balieri. 



Sheaths and spathes, at least on the upper part of the 



stem, enlarged. 5. A. ElUoliii. 



1. A. tenuispatheus Nash. Stems 5-15 dm. tall: spathes 2.5-3 cm. long, 

 fastigateh' crowded: racemes in pairs, 1-2 cm. long, protruding from the side 

 of the broad spathe: sessile spikelet 3-4 mm. long, the awn 10-15 mm. long. — 

 Everglades, pinelands and hammocks. — F. K. (Bah., Cuba, Ant.) 



2. A. longiberbls Hack. Stems 5-10 dm. tall, tufted: leaf-sheaths appressed- 

 hirsute: blades 5 dm. long or less, 7 mm. wide or less, those on the innovations 

 densely appressed-hirsute, those on the stem more or less so beneath, rough 

 above: spathes 3-5 cm. long, usually considerably exceeding the racemes, com- 

 monly brown : racemes 3-4 cm. long, stout : sessile spikelet 4—4.5 mm. long, 

 the awn straight or nearly so, 12-16 mm. long — Pinelands. — F. K. 



3. A. Tracyi Nash. Stems 5-8 dm. tall: spathes 4^5 cm. long, rather broad: 

 racemes 3—4 cm. long, rather stout : sessile spikelet 5 mm. long, the awn 

 1.5-2 cm. long. — Pinelands. 



4. A. Bakeri Scribn. & Ball. Stems stout, 8-12 dm. tall, tufted: leaf- 

 blades up to 4 dm. long, 4-7 mm. wide, flat ; spathes 4-5 cm. long ; racemes 1.5-3 



