Rutin, also called rutoside, quercetin-3-rutinoside and sophorin, is a citrus flavonoid glycoside found in buckwheat, the leaves and petioles of Rheum species, and asparagus. Rutin is also found in the fruit of the Fava D'Anta tree (from Brazil), fruits and fruit rinds (especially citrus fruits (orange, grapefruit, lemon, lime)) and berries such as mulberry and cranberries. Its name comes from the name of Ruta graveolens, a plant that also contains rutin. Rutin is the glycoside between the flavonol quercetin and the disaccharide rutinose. A powder is a dry, bulk solid composed of a large number of very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms powder and granular are sometimes used to distinguish separate classes of material. In particular, powders refer to those granular materials that have the finer grain sizes, and that therefore have a greater tendency to form clumps when flowing. Granulars refers to the coarser granular materials that do not tend to form clumps except when wet.