AIRA.] GR AMINES. 437 



coriaceous ; sheaths shining, smooth or rough, upper very long ; ligu'.e obtuse. 

 Panicle 4-8 in., linear-oblong, spreading in flower. Spikelets $ in., 

 very shining, fulvous or purplish ; empty glumes narrow, obtuse, shorter 

 than the flowering, keel scabrid or smooth, upper obscurely 3-nerved ; fl. 

 glumes 1-3 (3d always imperfect), silky at the base ; awn short, inserted 

 below the middle, variable in length. DISTRIB. N. and S. temp, and arctic 

 and mountain regions. A variable grass. 



Sub-sp. C^ESPITO'SA proper ; tall, leaves longer broader scabrid, branches of 

 panicle rough, awn inserted below the middle usually equalling the glume. 



Sub-sp. ALPI'NA, L. (sp. ) ; short, leaves narrower channelled smooth, branches 

 of panicle smooth, awn inserted at the middle shorter. A . Iceviyata, Sm. 

 Usual! v viviparous. Wet alpine rocks of Perth, Aberdeen, and Sutherland ; 

 ascending to 4, 100 ft. 



SUB-GEX. 2. Airop'sis, Desv. (gen.). Annual. Leaves setaceous. 

 Fl. glumes 2, with no rudimentary 3d, sessile, hardening, 2-cuspidate, 

 awned below the middle. Scales entire. Fruit grooved, adnate to the 

 hardened 11. glume and palea. (Intermediate between Aira and Avena.) 



3. A. caryophyl'lea, L. ; sheaths scabrid, panicle spreading, branches 

 long trichotoinous. 



Sandy meadows, &c. ; ascending to nearly 1,400 ft. in the Highlands ; fl. June- 

 July. Stems 2-10 in., tufted, leafless and scabrid above, bent below, often 

 purplish. Leaves setaceous, short, scabrid, obtuse ; ligule long. Panicle 

 1-2 in. Spikelets ^ in., ovate, shining; lower empty glume ovate, acumi- 

 nate, exceeding the' flowering, keel scabrid ; awn twice as long as its glume, 

 twisted. DISTRIB. Europe, N. Africa ; introd. in N. America. 



4. A. prse'cox, L. ; sheaths glabrous, panicle contracted, branches very 

 short with 1-2 spikelets. 



Dry pastures, &c. ; ascending to 1,800 ft. in Yorkshire ; fl. April-June. 

 Habit of A. caryophyllea, but panicle very different ; whole plant greener ; 

 spikelets narrower ; 2-fid points of flowering glume shorter ; awn inserted 

 higher up. DISTUIB. Europe ; introd. in N. America. 



SUB-GEN. 3. Coryneph'orns, Beauv. ('gen. ). Perennial. Leaves seta- 

 ceous. Fl. glumes entire, upper pedicelled, awn clavate bent bearded 

 above the base. Scales 2-fid. Fruit grooved, enclosed in the glume. 



5. A. canes'cens, L. ; tufted, leaves short rigid. 



Sandy coasts of Norfolk, Suffolk, and Kent, rare ; Channel Is. ; fl. July. 

 Tufts hard, rigid, pungent. Stems 4-8 in., rigid, bent below, glabrous 

 above. Leaves 1-2 in. , glaucous, involute ; upper sheaths long, scaberulous ; 

 ligule lanceolate. Panicle 1-3 in., narrow-oblong, spreading in flower; 

 branches thickened at the forks, short. Spikelets % in., narrow, pale 

 silvery or purplish ; empty glumes narrow, acuminate, tips hyaline ; fl. 

 glumes shorter, villous at the base ; keel channelled ; awn included or 

 shortly exserted, purple below, bearded at the middle where bent, above 

 gradually thickened, white anthers purplish. DISTRIB. Europe, Siberia. 



21. AVE'NA, L. 



Spi&elets large, terete or laterally compressed, panicled or racemed ; 2- or 

 more-fld., upper flower usually imperfect, lower rarely male only. Empty 



