Ideain, the cyanidin 3-O-galactoside, is an anthocyanin, a type of plant pigment.

Ideain is the main anthocyanin in red-skinned[1] or red-fleshed (for example Weirouge)[2] apple varieties.

It is also found in Chinese hawthorn fruits (Crataegus spp.).

[3] It is also the pigment in the copper beech (cultivar of Fagus sylvatica), that was identified in 1932.

[7] Quintinia serrata, the tawheowheo, a species of evergreen trees endemic to New Zealand, has different patterns of anthocyanins (cyanidin 3-O-glucoside and cyanidin 3-O-galactoside) in its leaves to protect the shade-adapted chloroplasts from direct sun light.