166 TRIANDRIA— DIGYNIA. Avena. 



On lofty alpine rocks in Scotland. 



Found by the late Mr. G. Don in 1807., upon the rocky summits 

 of the highest mountains of Clova, Angusshire. 



Perennial. July. 



Root of several strong downy fibres, tufted, not creeping. Stem 

 2 feet high, erect, round, striated, smooth, leafy in the lower 

 half. Leaves linear, rough-edged, or minutely serrated, flat, 

 naked, with many rough ribs ; the radical ones folded, at least 

 when dry, and their extreme margin inflexed ; but none of the 

 leaves are involute, as in A. pratensis, nor so strongly serrated. 

 Sheaths cylindrical, strongly ribbed, rough to the touch j the 

 uppermost very long. Stipula triangular, acute, jagged ; the 

 uppermost somewhat elongated. Panicle 3 or 4 inches long, 

 erect, of a pale silvery brown, but little variegated -, branches 

 furrowed, or compressed, rough at the opposite sides with mi- 

 nute erect bristles ; tumid and angular at the summit 3 the 

 lowest divided or branched ; the rest simple, erect, often very 

 short and thick. Spikelets erect, an inch long at most. Calyx- 

 valves lanceolate, concave, each with 3 principal rough ribs, the 

 points acute, thin and pellucid. Florets 5 or 6, two-ranked, 

 rather distant, each subtended by a large tuft of bristly hairs, 

 slightly decurrent, but the rest of the partial stalk is nearly 

 naked. Outer valve of the corolla much like the calyx, but 

 somewhat rougher, and 5 -ribbed ; deeply cloven at the point. 

 Awn terminating the keel about the middle of the glume, brown, 

 rough, partly silky ; its lower half strongly twisted when diy 5 

 upper bent variously, taper-pointed. The inner valve is lanceo- 

 late, extremely thin, flat, with finely downy, not inflexed, edges, 

 nor any traces of ribs 5 the point acute, torn, not cloven. 



A specimen from Professor Schrader of his A. planiculmis proves 

 different from our plant j having a strong widely-creeping root ; 

 the stem, as well as the sheaths, which clothe its lower part, 

 compressed ; leaves much broader and all flat ; panicle a span 

 long, more compound, variegated with purple ; spikelets one 

 third smaller ; and the hairs on their partial stalks mucli less 

 tufted. 



6. A. flavescens. Yellow Oat-grass. 



Panicle much branched, spreading, erect. Florets about 

 three, longer than the very unequal calyx. Leaves flat, 

 a little downy. Root somewhat creeping. 



A. flavescens. Linn. Sp. PI. 1 1 8. mild. v. 1 . 449. Fl. Br. 142. 



Engl. Bot. v. 14. t. 952. Curt. Lond.fasc. 3. t.5. Knapp t.89. 



Hook. Scot. 44. Sincl.39. Schracl. Germ, v.], 377- Host Gram. 



v. 3. 26. t. 38. Schreb.Gram.vA.76.t.9. Leers 44. t.lO.f. 5. 



Ehrh. Calam. 56. 

 A. n. 1497. Hall, Hist, v. 2. 233. 



