Linked from
The 15 pages that link to Barley, each with the reason it gives.
CaryopsisRelated: Barley grains are caryopses, often retained within a hull.
Gluten-free dietRelated: Malt and many barley products are incompatible with the diet.
Beta-glucanRelated: Barley supplies beta-glucan with a structure similar to oat beta-glucan.
SwatherRelated: Swathing barley can allow the crop to dry in rows before combining.