169 



GRASS FAMILY. 

 2. Aira praecox L. Early Hair-grass. (Fig. 386.) 



Aira praecox L,. Sp. PI. 65. 1753. 



Glabrous and smooth throughout, culms 2'-$' 

 tall, erect, from an annual root, simple, rigid. 

 Sheaths clothing the whole culm, the upper one 

 often enclosing the base of the panicle; ligule about 

 long; leaves V longer less, involute-setaceous; 

 panicle contracted, strict, K'-i' in length; spike- 

 kts about \y z " long, the empty scales acute; the 

 flowering scales acuminate, 2-toothed, about \y 2 " 

 long, bearing an awn \}>->"-2" long. 



In dry fields, southern New Jersey and Pennsyl- 

 vania to Virginia. Naturalized from Europe. May 

 July. 



42. DESCHAMPSIA Beauv. Agrost. 91. pi. 18. f. 3. 1812. 



Perennial grasses with flat or involute leaves, and contracted or open panicle*. SpikeleU 

 2-flowered, both flowers perfect, the hairy rachilla extended In-yond tin H.. \MTS or rarely 

 terminated by a staminate one. Scales 4 (rarely more), the 2 lower enij.t icutr, 



membranous, shining, persistent; the flowering scales of about the same texture, dtvidnooa, 

 bearing a dorsal awn, the apex toothed. Palet narrow, 2-nerved. Stamens 3. Style* distinct. 

 Stigmas plumose. Grain oblong, free, enclosed in the scale. [In honor of J . C . A. Loueleur- 

 Deslongchamps, 1774-1849, French physician and botanist. ] 



About 20 species, inhabiting cold and temperate regions, a few occurring in the high 

 of the tropics. Besides the following, some 6 others occur in the western part* if North 



Upper flowering scale reaching or extending beyond the apex of the empty scale*. 



Flowering scales about iK" long, erose -truncate; leaves flat. i / 



Flowering scales about 2" long, acute or obtuse; leaves involute. 

 Empty scales extending much beyond the upper flowering scale. ; /' mlropmrpm 



i. Deschampsia caespitosa (I,.) Beauv. Tufted Hair-grass. (Fig. 387.) 



Aira caespitosa I.. Sp. PI. 64. 



Descham/>sia caespitosa Beauv. Affroct 160. />/ 



1812. 



Culms 2-4 tall, erect, simple. smooth and gla- 

 brous. Sheaths much shorter than the mtrr:. 

 ligule i "-3" long; leaves flat. 

 smooth beneath, strongly scabrous above, the banl 

 ones numerous, one-quarter t one-half a* long a 

 the culm, those of the culm 2'-6' long; panicle open, 

 3 / -9 / in length, the branches widely spreading or 

 ascending, often somewhat fli -v ^ed t the 



base, the lower 2'~s' long: ipfl 

 flowering scales aUnit i ' + " 1"ti.i;. i row-truncate 

 the apex, the awns somewhat -.hotter or a B 

 longer, the upper scale reaching to or extending 

 beyond the apices of the empty one*. 



Newfoundland to Alaska south to >rjenejr; : 

 nois, Minnesota and in the R ; 

 Sierra Nevada to New Mexico and |C. 

 wet soil. Also in Europe and Aau. Jal 



