This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
This grass is found on hills in the north of England and Scotland. The habit is creeping. The upper sheath is equal to the leaf in length. The ligule is large, blunt. The panicle is erect, spreading. The plant is 9-18 in. in height. It flowers in July and August, and is a herbaceous perennial.
The habitat of this species is dry rocks, walls, dry calcareous places. The plant has the grass habit. The plant is often purplish in colour, smooth. The root is fibrous. The stems are slender, wiry, erect. The leaves are nearly flat or have the margin inrolled, and are more or less bristle-like. The sheaths are round and grooved, The ligule is oblong. The panicle is lance-shaped, nearly simple, rigid, compact, the branches distichous. The spikelets are 3-5, more or less stalkless, linear, with a narrow point. The rachis is broadly channelled, rough at the edge. The upper glumes reach as far as the third floret. The flowering glumes are smooth, shining, round, 7-10, acute, with faint nerves. The flower-stalks are short, stout, half-round in section. The plant is 3-6 in., flowering in June and July, and is a herbaceous annual.
Agropyron dontanum, F. B. White =A. a/pitium, Don = T. biflorum, Brigh. Mitt. - The habitat of this species is mountain cliffs. The plant is erect, and the leaves are thin and flat, with many slender ribs. The panicle is close. The spikelets are 2-6-flowered. The glumes have a short awn, and are strongly 4-6-ribbed, the awn, ribs, edges, and tips rough. The lower palea is narrowed abruptly, and has membranous margins at the tips, 4-6-ribbed, with an awn quarter to half its length. The upper palea is blunt-pointed, densely fringed with hairs on the lateral keels, densely rough with a prominent midrib towards the tip, the lateral ribs toothed at the tip, which fall short of the apex. The axis is hairy, the rachis fringed with hairs. The plant is 1-2 ft. high, flowering in July and August, and is a herbaceous perennial.