Basic colour: Various jewel-like colours - gold, copper, green, blue, violet, purple, magenta, sometimes black.
Pattern colour: None
Number of spots: None
Other colour forms: Many and common
Pronotoum: As basic colour
Leg colour: As basic colour
Confusion species: Plateumaris sericea
P. discolor may be a synonym of P. sericea, since P. sericea with smooth pronota intergrade with P. discolor with wrinkled pronota. For a discussion, see J. Bratton & M. Greenwood (1997.) British reed beetles, Plateumaris and Donacia (Chrysomelidae): an identification aid using pronotum surface characters. Latissimus 8: 11-14. However, the Atlas of British and Irish species (Cox 2007), the latest checklist (Duff 2012) and the recent AIDGAP key (Hubble 2012) all consider them to be different species with intermediate forms.
Habitat: Various wet habitats, usually more acidic than those favoured by P. sericea.
Host plant: Usually sedges (Carex spp.), sometimes other wetland plants
Food: Adults on pollen of various plants, larvae at roots and rhizomes of cotton-grasses (Eriophorum spp.) growing among Sphagnum.
Other notes: Separation from P. sericea may require dissection of males to investigate the aedeagus.