GENUS 77. 



GRASS FAMILY. 



2. Diplachne acuminata Nash. Sharp- 

 scaled Diplachne. Fig. 568. 



D. acuminata Nash, in Britt. Man. 128. 1901. 



Culms tufted, i-2 tall, finally branching; 

 blades erect, 4'-! long, 22" wide or less, usually 

 involute when dry, very rough ; racemes numer- 

 ous, erect or ascending, the larger 3'-6' long; 

 spikelets 5 "-6" long, the scales 8-u, the flower- 

 ing scales 3"-3^" long, acuminate at the entire or 

 occasionally slightly 2-toothed apex, the lateral 

 nerves rarely slightly excurrent, the midnerve ex- 

 tending into an awn 4" long or less. 



Wet or moist soil, Arkansas and Missouri to Ne- 

 braska and Colorado. June-Aug. 



3. Diplachne maritima Bicknell. Long- 

 awned Diplachne. Fig. 569. 



Festuca procumbens Muhl. Gram. 160. 1817. 

 Diplachne procumbens Nash, in Small, Fl. SE. U. S. 145. 



1903. Not Arech. 1896. 

 D. maritima Bicknell, Bull. Torrey Club 35: 195. 1908. 



Culms tufted, finally branching, S'-i6' tall ; blades 

 erect, 3'-8' long, 2" wide or less, involute when dry ; 

 racemes numerous, erect, the larger 2'-3' long; 

 spikelets about 5" long ; scales 8-10, the empty ones 

 usually awned or awn-pointed, the flowering scales, 

 exclusive of the awn, 2i"-4*" long, acuminate at 

 the slightly 2-toothed apex, the midnerve extending 

 into an awn * or more as long as the scale. 



Brackish marshes and shores, Massachusetts to South 

 Carolina ; also on the shore of Onondaga Lake, N. Y. 

 Aug.-Oct. 



78. AIRA L. Sp. PI. 63. 1753. 

 [MOLINIA Schrank, Baier. Fl. i : 100. 1789.] 



Perennial tufted grasses, with narrow flat leaf-blades and paniculate inflorescence. 

 Spikelets 2-4-flowered. Two lower scales empty, somewhat obtuse or acute, unequal, shorter 

 than the spikelet ; flowering scales membranous, rounded on the back, 3-nerved ; palets 

 scarcely shorter than the scales, obtuse, 2-keeled. Stamens 3. Styles short. Stigmas short, 

 plumose. Grain oblong, free, enclosed in the scale and palet. [Greek name for Lolium 

 tciintlc'ituin.] 



A genus of a few species, natives of Europe and Asia. Type 

 species : .-lira cocntlea L. 



i. Aira coerulea L. Purple Melic- or Moor Grass. 

 Lavender-grass. Indian-grass. Fig. 570. 



Aira coerulea L. Sp. PL 63. 1753. 

 Molinia coerulea Moench, Meth. 183. 1794. 



Culms i-3i tall, erect, simple, smooth and glabrous. 

 Sheaths overlapping and confined to the lower part of the 

 culm, smooth and glabrous ; ligule a ring of very short 

 hairs; blades 4'-! long or more, i"-3" wide, erect, acu- 

 minate^ smooth beneath, slightly scabrous above ; panicle 

 3'-io' in length, green or purple, the branches usually 

 erect, i'-4' long; spikelets 2-4- flowered, 2 "-4" long; empty 

 scales acute, unequal ; flowering scales about 2" long, 

 3-nerved, obtuse. 



Sparingly introduced on ballast and in waste places, Maine to 

 New York. Adventive from Europe. Aug.-Sept. 



