140 POAOEAE 



1. Acamptoclados sessilispicus (Buckl. ) Nash. Stems 2-14 dm. tall, erect, sim- 

 ple : leaf-sheaths crowded at the base of the stem, hairy at the summit ; blades 5-15 cm. 

 long, 1.5-3 mm. wide, rough above: panicle 1-4 dm. long, its branches stout and rigid: 

 s^jikelets 4-6-flowered, the flowering scales 4 mm. long. [Eragrostis sessilispicu Buckl. j 



On prairies, Kansas to Texas. Summer and fall. 



91. BUIiBILIS Raf. 



Perennial creeping stoloniferous grasses, with narrow flat leaf-blades and the inflores- 

 cence of two forms, one staminate, consisting of one-sided spikes approximate at the sum- 

 mit of long-exserted stems, the other pistillate, on short stems, composed of small spike- 

 like clusters barely exserted from the sheath. Spikelets dioecious, sessile, very unlike. 

 Staminate spikelets 2-3-flowered, crowded in 2 rows on one side of the short flattened 

 spikes ; scales 4 or o, membranous ; stamens 3. Pistillate spikelets 1-flowered, the larger 

 scales united at the base and involucre-like ; scales 3, the 2 outer empty, the first mem- 

 branous, usually small, sometimes similar to the second which is the largest, firm, concave 

 at the base, 3-lobed at the apex, tlie flowering scale narrow, nearly hyaline, enclosing a 

 broad convolute 2-nerved palet and a flower. Styles distinct, long. Stigmas elongated, 

 short-plumose. 



1. Bulbilis dactyloides ( Nutt. ) Raf. Stoloniferous. Staminate stems 1-3 dm. tall, 



erect, slender, naked above : pistillate stems 1-8 cm. long, much exceeded by the leaves : 



leaf-blades 2 mm. wide or less, papillose-hirsute, those on the staminate stems 2-10 cm. 



long, erect, those on the stolons and pistillate stems 2.5 cm. long or less and spreading : 



staminate spikes 2 or 3, approximate, the 2-3-flowered spikelets 4-5 mm. long, flattened : 



pistillate spikelets ovoid, the outer scales indurated. 



On plains and prairies, Minnesota to North Dakota, Arljansas and Texas. Also in Mexico. Sum- 

 mer. Buffalo Gkass. 



92. PAPPOPHORUM Schreb. 

 Perennial tufted grasses, with narrow leaf-blades and dense spike-like panicles. Spike- 

 lets usually 1-2-flowered, narrow. Scales usually 4-6 ; the 2 lower empty, acute, carinate ; 

 flowering scales firm, divided into many awn-like lobes. Stamens 3. Styles short, distinct. 

 Stigmas plumose. 



1. Pappophorum apertum Miuiro. Stems tufted, 5-10 dm. tall, erect, rather stiff, 

 finally somewhat branched : leaf-sheaths pubescent at the summit on the outside ; blades 

 3dm. long or less, usually involute: panicle 1-2 dm. long, narrow, its branches erect: 

 spikelets 7-8 mm. long, including the awns, the flowering scales pubescent on the margins 

 and keel for l their length. 



In dry soil, central Texas to Arizona. Also in Mexico. Spring and summer. 



93. MONANTHOCHLOE Engelm. 



Perennial creeping or stoloniferous monoecious grasses, with short rigid convolute often 

 curved leaf-blades crowded at the nodes, and an inconspicuous inflorescence concealed 

 among the leave-i. Spikelets unisexual, the staminate hardly differing from the pistillate, 

 2-flowered, rarely 3-flowered, usually sessile and in piirs, or stipitate and single, in the leaf 

 fascicle-i, the rachilla continuous and prolonged beyond the flower and sometimes bearing a 

 short terminal scale. Scales 4 or 5, the 2 outer empty, somewhat resembling the floral 

 leaves, distichous, membranous and sheathing at the base, linear, rigid and spreading 

 above, many-nerved, the remaining scales membranous, firmly hyaline, obtuse or denticu- 

 late, enclosing a 2-nerved convolute palet and a flower. Stamens 3. Styles distinct, long. 

 Stigmas elongated, shortly Ijarbellate-plumose. 



1. Monanthochloe littoralis Engelm. Branches densely tufted from creeping stems, 



1-5 dm. tall, stiff, wiry : leaf-blades crowded on short branches, widely spreading, 1.5 cm. 



long or less, stiff, often curved. 



In sand along theseacoast, southern Florida and southern Texas and Lower California. Spring 

 and summer. 



94. MUNROA Torr. 

 Low annual tufted grasses, with many rigid and often creeping dichotomously or fascic- 

 ulately branched stem, short rigid spinescent leaves which are crowded at the nodes or at 



