POACEAE 14 



F. 



nerve often excurrent as a short tip ; palet sliorter tlian the soalo, 2-nerved. Stamens 3. 

 Styles long, distinct. Stigmas short, plumose. 



1. Redfieldia flexuosa ( Thurb. ) Vasey. Stems 1 m. tall or less, from a stout rootstock : 

 leaf-blades elongated, 2-6 dm. long, 2-4 mm. wide, smooth : panicle loose and open, 1.5-5 

 dm. long, its branches spreading or ascending, the larger 7-15 cm. long, tlieir divisions 

 spreading and more or less flexuous : spikelets 5-6 mm. long, on slender spreading pedicels ; 

 scales 4-7 ; the 2 outer empty, acuminate ; iiowering scales 5-6 mm. long, acuminate, tiie 

 callus densely pilose with long liaii*s. 



On prairies, Nebraska and Wyoming to the Indian Territory and Colorado. Summer and fall. 



101. DIPLACHNE Beauv. 

 Tufted often tall grasses, with narrow flat leaf-blades and an inflorescence usually com- 

 posed of numerous long slender spikes or racemes (rarely reduced to one and terminal), 

 racemosely arranged on a long axis. Spikelets linear, sessile or nearly so, often scattered 

 along and appresscd to the rachis, many-flowered, the flowers [jcrfect or the upper ones 

 staminate. Scales many, membranous, the 2 lower empty, persistent, keeled, acute, un- 

 equal, the remaining scales larger, the apex often 2-toothed and mucronate or short-awned 

 between the teeth ; palet shorter tiian the scale, hyaline, 2-nerved or 2-keeled. Stamens 

 3. Styles distinct. Stigmas plumose. 



Inflorescence of a single raceme. 1. B. spicata. 



Inflorescence of o-ma7iy racemes. 



Flowering scales entire or shortly and acutely 2-toothed at the apex, usually 

 awned or awn-tipped. 

 Palet pilose on the infolded margins. 



Awn less than i., as long as the body of the flowering scale. 



Spikelets 4-8 mm. long, the flowering scales acute or obtuse at the 2- 



toothed apex, the lateral nerves often excurrent. 2. D. fa$ciciU(irii<. 



Spikelets 10-12 mm. long, the flowering scales acuminate at the usually 



entire apex, the lateral nerves rarely excurrent. 3. D. acuminata. 



Awn 1.2 as long as the body of the flowering" scale or more. 4. D. procunibenis. 



Palet not pilose on the infolded margins. 5. £>. Halci. 



Flowering scales usually awnless, 2-toothed at the apex, the teeth broad and 



rounded. 6. D. dubia. 



1. Diplachne spicata Doell. Stems densely tufted, 1-2 dm. tall, naked above, twice 

 as long as the innovations or more : leaf-sheaths short, more or le.ss pilose at the apex ; 

 blades erect, sparingly pilose, 0.5 mm. wide, involute, tho.se on the stem 3 cm. long or les,s, 

 those on the innovations longer : inflorescence of a single raceme, 4-10 cm. long : spikelets 

 7-8 mm. long ; scales 8-10, tlie lower empty ones rather narrow, tlie flowering scales, ex- 

 clusive of the awn, about 3 mm. long, the nerves glabrous, the lateral ones vanishing below 

 the apex, the midnerve excurrent in an awn 0.75-1.5 mm. long, the apex 2-toothed, a tuft 

 of long hairs on the rachilla at the base of the palet. 



Among rocks, central Texas to Mexico. Summer and fall. 



2. Diplachne fascicuJaris (Lam.) Beauv. Stems tufted, finally branched, 3-8 dm. 

 tall, somewhat exceeding the innovations to twice their length : lower leaf-sheaths often 

 rough; blades erect, 1-2 dm. long, 3 ram. wide or less: involute when dry, rough, the 

 uppermost one often equalling or exceeding the inflorescence : inflorescence usually partiallv 

 included at the base, its 8 or more racemes erect or erect-ascending, the larger ones 4-8 cm. 

 long : spikelets 6-8 nnn. long ; scales 10-12, the lower empty ones acute, the flowering 

 .scales, exclusive of the awn, 3-4 mm. long, the apex commonly 2-toothed, the nerves pilose 

 below the middle, the lateral nerves usually slightly excurrent, the midnerve extending 

 into an awn 1 mm. long or less. 



Along the coast, Florida to Texas, and in the Mississippi Valley to Missouri. Summer and fall. 



3. Diplachne acuminata Nash. Stems tufted, 3-6 dm. tall, finally branched : leaf- 

 sheaths rough at the summit ; blades erect, 1-3 dm. long, 4.5 mm. wide or less, usually 

 involute when dry, very rough, uppermost one generalh- exceeding the inflorescence : in- 

 florescence partly included at the base, the exserted portion 2.5 dm. long or less, its 

 branches and the main axis rough, the former erect or ascending, the larger 0.7-1.5 dm. 

 long: spikelets 10-12 mm. long ; scales 8-11, the lower empty ones acuminate, the flower- 

 ing scales 6-7 mm. long, acuminate at the entire or occasionally slightly 2-toothed apex, 

 the lateral nerves rarely sliglitly excurrent, the midnerve extending into an awn 0.75-1.3 

 mm. long, the lateral nerves pilose below tlie middle, the midnerve rarely slightly so at the 

 base. 



In wet or moist soil, Nebraska and Colorado to Arkansas. Summer. 



4. Diplachne procumbens (Muhl.) Xash. Stems tufted, finally branched, 2-4 dm. 

 tall : leaf-sheaths smootli ; blades erect, 8-20 cm. lone, 4 ram. wide or less, involute when 



10 



