56 POACEAE 



8. Erianthus Smallii Nasli. Stems 1.5-2.5 m. tall, the nodes pubescent with readily 

 deciduous hairs, the summit and the jxinicle-axis copiously appressed-pubescent with long 

 silky hairs. Leaf-sheaths usually sparingly hirsute at the apex, otherwise glabrous ; blades 

 1.5-7 dm. long, 6-20 mm. wide, rough on both surfaces: panicle 2-4 dm. long, 4-6 cm. 

 wide, its branches erect, the larger 7-10 cm. long : spikelets crowded, about equalling the 

 basal hairs and 2 again as long as the internodes ; 2 outer scales 8-9 mm. long, pilose with 

 long hairs ; fourth scale 2-toothed at the apex, the teeth long and subulate, the awn 2-2.5 

 cm. long, the included portion long and tightly spiral, the remainder loosely spiral. 



In low grounds, Tennessee to Georgia, Florida and Mississippi. Fall. 



9. Erianthus strictus Baldw. Stems 1-2 m. tall, the nodes usually pubescent with 

 readily deciduous hairs, the summit and the panicle-axis glabrous. Leaf-sheaths glabrous ; 

 blades" 2-7 dm. long, 5-10 mm. wide, rough on the margins but otherwise smooth : pan- 

 icle 2-4 dm. long, 1-2 cm. wide, its branches appressed, the larger 5-8 cm. long : spikelets 

 crowded, aliout 2 again as long as the internodes, the basal hairs wanting or sparse and less 

 than :^ as long as the spikelet ; 2 outer scales 8-10 mm. long, strongly appressed-hispid ; 

 fourth scale entire or shortly 2-toothed at the apex, the awn 1.5-2 cm. long, straight. 



In moist soil, Tennessee to Florida and Texas. Fall. 



4. MANISURIS L. 



Perennial, often tall grasses, sometimes with rootstocks, narrow flat leaf-blades, and 

 cylindric articulated terminal and axillary spikes. Spikelets in pairs at each joint, in ex- 

 cavations in the rachis, one sessile and containing a perfect flower, the other pedicellate 

 and either bearing a staminate flower, or empty. Scales of the sessile spikelet 4, the 

 outermost thick and coriaceous, sometimes more or less rugose or pitted, concealing, to- 

 gether with the pedicel of the other spikelet, the remaining .scales and the excavation in 

 the rachis ; second scale chartaceous, the third and fourth scales hyaline, the former empty 

 or infolding a staminate flower, the latter enclosing a thinly hyaline palet and perfect 

 flower. Scales of the pedicellate spikelet 4 or fewer. Stamens 3. Styles distinct. 

 IRottboellia L. f.] Kat-tail Grass. 



Stems from horizontal rootstocks, round ; sheaths round, narrow. 1. M. cylindrica. 



Stems tufted, much flattened, at least below ; rootstocks wanting ; sheaths much com- 

 pressed, broad, keeled. 

 First scale of the sessile spikelet transversely wrinkled (rarely smooth). 



Wrinkles short, but little elevated, tubercle-like, sometimes entirely wanting. 2. M. tuberculosa. 

 Wrinkles long, often extending completely across tlie scale, much elevated. 

 Leaf-blades rather short and broad, especially those of the upper sheaths, 



6-10 mm. wide at the base : rachis of the racemes glabrous. 3. M. Chapmanii. 



Leaf-blades elongated and narrow, even those of the upper sheaths, 6 mm. 



wide at the base or less : rachis of the racemes puberulent. 4. M. rugosa. 



First scale of the sessile spikelet pitted. 5. M. tessellata. 



1. Manisuris cylindrica (Michx. ) Kuntze. Stems from creeping rootstocks, round, 

 3-10 dm. tall, slender : leaf-sheaths round, narrow ; blades 3 dm. long or less, 1-3 mm. 

 wide : racemes finally exserted, 1-2 dm. long, straight or curved, the rachis barely if at all 

 contracted at the nodes : sessile spikelet 4.5-5 mm. long, about ecpialling the internode, 

 the first scale more or less pitted in longitudinal lines, or rarely unpilted, each pit often con- 

 taining a subulate hair ; pedicellate spikelet reduced to 1 or 2 short scales, the pedicel 

 linear, shorter than the sessile spikelet and curved around its margin. {^RoUboellia cylin- 

 drica (Michx.) Chapm.] 



In sandy soil, Georgia and Florida to Texas ; also in Missouri and the Indian Territory. Summer_ 



2. Manisuris tuberculosa Nash. Stems tufted, much compressed, 8-12 dm. tall, 

 stout : leaf-sheaths much flattened, broad, keeled ; blades 3 dm. long or less, 3-7 mm. 

 wide : racemes Anally exserted, 6-10 cm. long, straight, the rachis barely if at all contracted 

 at the nodes : sessile spikelet about 4 mm. long, about eqiuilling the internode, the flrst 

 scale transversely wrinkled, or very rarely without wrinkles, the wrinkles short, tubercle- 

 like, irregularly disposed ; pedicellate spikelet reduced to 1 or 2 short scales about ^ the 

 length of the linear pedicel which is a little .shorter than the sessile spikelet and curved 

 around its margin. 



On lake shores, peninsular Florida. Summer. 



3. Manisuris Chapmanii (Hack.) Nash. Stems tufted, 6-15 dm. tall, much com- 

 pressed : leaf-sheaths much flattened, broad throughout ; blades usually less than 2.5 dm. 

 long, 6-10 mm. wide, those of the inflorescence generally very short and broad : racemes 

 commonly 4-5 cm. long, occasionally longer, little compressed, exserted or a little included 

 at the base, the rachis glabrous, the internodes and pedicels usually flat, not much de- 

 pressed on the back : sessile spikelet 4-5 mm. long, usually exceeding the stout inter- 



