TRIAND. DIGYK. 29 



glabrous. Leaves linear-acuminate. Panicle brownish, shining. 

 Spikelets broadly ovate. Cal. valves ovate, acute, rather unequal, 

 sometimes a little serrated at the point. Florets rather longer than 

 the c.al. and the outer valves of a firmer texture, scabrous when 

 highly magn., distinctly fringed at the margin, the point sharp but 

 not awned. Central floret the smallest. 



17. AIRA. 



* Corolla awnless. 



1. A. crislata (crested Hair-grass), panicle spiked, florets longer 

 than the cal., glumes acuminate, leaves hairy. Lightf. p. 98 

 (Poa cristatd). E. B. t. 648 (Koeleria Per's.). 



HAB. Dry and mountainous pastures, frequent, Lightf. About Port 

 Patrick, abundant. FL June, July. "}/ . 



Six to eight inches high. Leaves linear, short, glaucous. Spike shi- 

 ning, ovato-lanceolate. Spikelets ovate-lanceolate. Glumes all 

 acute or slightly acuminate, lanceolate, compressed, glabrous, or 

 a little rough at the keel, inner valves of the cor. white, mem- 

 branous. 



2. A. aqualica (Water Hair-grass), panicle spreading, glumes 

 obtuse, florets longer than the cal. Lightf. p. 94. jE. B. 

 t. 1557. 



HAB. Banks of rivulets and ponds, but not common, Lightf. Near 

 Dumbarton, Dr. Brown. Wet fields a little to the E. of Gilbert- 

 field Castle, abundantly, Hopk. Fl. June. If . 



Culms one or one foot and a half long, ascending. Leaves linear- 

 lanceolate, obtuse. Panicle erect, branches spreading. Spikelets 

 oblong. Cal. valves very small, unequal, plane, purplish, obtuse, 

 and bluntly toothed at the extremity. Florets thrice the length of 

 the cal. upper ones pedunculated, their valves concave, brown, with 

 green ribs, diaphanous at the point. 



** Corolla awned. 



3. A. ccespitosa (turfy Hair-grass), panicle diffuse, branches 

 scabrous, florets villous at the base rather longer than the cal., 

 awn strait inserted near the base of and not exceeding the cor., 

 leaves plane. Lightf. p. 94. E. B. t. 1453. 



HAB. Moist and rather shady places, abundant. Fl. July, Aug. If. . 



Much tufted in its growth. Culms 2 4 feet high. Leaves linear, 

 acuminate, rigid, rough at the margin. Panicle large, silvery gray 

 or greenish, much branched. Spikelets acute. Cal. valves un- 

 equal, lanceolate, subglabrous, rather acute, erose. Florets with a 

 few longish hairs at the base, upper ones pedunculated, their valves 

 ovate, obtuse, erose. Mr. D. Don in his unpublished MSS. enu- 

 merates the following varieties of this common grass as natives of 

 Scotland. /3. vivipara, on the sea-shore, y. glomerata, branchlets 

 clustered j on the Clova mountains, G. Don. $. gracilis, slenderer, 

 leaves shorter; meadows in Angus-shire, G. Don. 



4. A. alpina (smooth Hair- grass,), panicle subcoarctate, 

 branches and pedicels perfectly smooth, florets villous at the 



