In traditional classifications of barley, these morphological differences have led to different forms of barley being classified as different species.
Under these classifications, two-row barley with shattering spikes (wild barley) is classified as Hordeum spontaneum K. Koch.
Two-row barley with nonshattering spikes is classified as H. distichum L., six-row barley with nonshattering spikes as H. vulgare L. (or H. hexastichum L.), and six-row with shattering spikes as H. agriocrithon Åberg.

Because these differences were driven by single-gene mutations, coupled with cytological and molecular evidence, most recent classifications treat these forms as a single species, H. vulgare L.
In traditional classifications of barley, these morphological differences have led to different forms of barley being classified as different species. Under these classifications, two-row barley with shattering spikes (wild barley) is classified as Hordeum spontaneum K. Koch. Two-row barley with nonshattering spikes is classified as H. distichum L., six-row barley with nonshattering spikes as H. vulgare L. (or H. hexastichum L.), and six-row with shattering spikes as H. agriocrithon Åberg.
Because these differences were driven by single-gene mutations, coupled with cytological and molecular evidence, most recent classifications treat these forms as a single species, H. vulgare L.
Barley