Almost ubiquitous in some places, Wall Barley is found in the North Temperate Zone in Europe from Scotland southward, and in North Africa. It is found in the whole of South Britain, but not in Brecon, Radnor, and Flint in Mid, and N. Britain in the Trent, Mersey, Humber provinces, except in S.-E. Yorks, Tyne district, only in Cumberland in the Lakes province. In Scotland it is found in Wigtown, Ayr, Roxburgh, Berwick, Haddington, Edinburgh, Linlithgow, Fife, Stirling, Forfar, Kincardine, Elgin, Caithness, or as far north as Caithness, and in E. Scotland generally. It is very rare in Ireland and the Channel Islands.

Wall Barley is a common plant in all waste places, growing in dense masses on ground awaiting building-operations, along the boundaries of gardens, along the roadside, in towns as well as in villages. It also grows in cultivated fields, where it is better developed.

The stems are numerous, sub-erect, prostrate then ascending, below leafy, jointed, with large nodes paler than the stem. The leaves are small, long, broad, bluish-green, downy, with inflated sheaths. The ligule is very short.

The spike is flattened at the side, drooping, pale-green, flat, stout. The spikelets are in threes, overlapping, dense, with linear-lance-shaped glumes fringed with hairs in the middle spikelet, lateral, bristle-like, rough. The awn is longer than the glumes, the flowering glumes are lance-shaped, the empty glumes thread-like.

The plant is 1 ft. high. It flowers in June and July. It is annual, and propagated by seeds. The lateral flowers are male, those in the middle bisexual or hermaphrodite. There are 2 long, pointed nectaries at the base of the ovary. The anther-stalks are threadlike, the anthers yellowish-green and small. There are 2 styles, bent back and softly hairy, and the stigmas are nearly stalkless and feathery. The flowers are anemophilous, or pollinated by the wind. In Barley the flowers open between 5 and 6 a.m., at as low a temperature as 12 1/20 C. The middle florets are cleistogamic. The fruit adhering to the palea is light and adapted for wind dispersal, and the long awn may catch in wool, etc., and cause the seeds to be dispersed by animals.

This common grass is a sand-loving plant growing on a sand soil.

The Wall Barley Grass is infested by a cluster-cup fungus, Us-tilago segetum and Pyrenophora trichostoma. The moths The Antler (Charaeas graminis), Gelechia cerealella are found on it.

Hordeum is found in Virgil as the Latin for barley, and the second name indicates the mural habitat.

It is called Mouse, Wall, Way, or Wild Barley, Way Bennet, Way Bent, Rye Grass, Squirrel-tail Grass, Purr Barley, Pussies, the last referring to the habit boys have of putting the long-awned, flowering spikes down the sleeve.

It is called St. Peter's Corn in Germany. So injurious is it to the teeth of horses that the best advertisement for an inn there, it was said, would be "Hay without any mixture of Squirrel Grass".

Essential Specific Characters:345. Hordeum murinum, L. - Stem glabrous, erect, leaves long, flat, glumes of middle spikelet ciliate, linear, lateral, spikelets imperfect.