- Latin synonym: Nymphalis c-album
- Family: Brushfooted Butterflies – Nymphalidae
- Subfamily: True Brushfoots – Nymphalinae
- Wing span: Medium-sized, 40–50 mm (1.57–1.97 in.)
- Wing upper side: Orange, with black blotches and margins. Hind wing’s black margin and orange blotches, which can also continue to forewing. Very tip of forewing with white or yellowish white blotch.
- Wing underside: Marbled brown and black. Middle of hind wing with white narrow arc. Both wings with row of bluish green blotches close to the margin.
- Habitat: Half-open forests, edges of logging areas. Also culturally-influenced areas.
- Flying time: Mid-April–mid-June, then mid-July–late September (noticeably more common).
- Overwintering form: Adult butterfly.
- Larval foodplant: Caterpillar is a polyfag, i.e. eats several different species such as stinging nettle (Urtica dioica), birches (Betula), currants (Ribes) and hops (Humulus lupulus).
The comma is quite common in Finland as far north as Oulu. It bears some similarity to the small tortoiseshell, but the species can be told apart by e.g. the lack of white blotches on the upper surface of the small tortoiseshell’s wings and from other tortoiseshells by its lobe-edged wings. An excellent identification marker is the pale c-shaped arc on the underside of its hind wings, which has given it its Latin generic name c-album (white c). Commas that fly in Finland in the spring have overwintered as adults, and their colours are clearly less vibrant than second-generation butterflies.
Males wait for females in forest clearings and margins, where they defend their territory. The females lay their eggs one by one on the leaves of the host plant. The caterpillar is protected in a web underneath a leaf and builds a cocoon into the stalk.