Pinguicula vulgaris

It grows to a height of 3–16 centimetres (1.2–6.3 in), and is topped with a purple, and occasionally white, flower that is 15 millimetres (0.59 in) or longer, and shaped like a funnel. This butterwort grows in damp environments such as bogs and swamps, in low or subalpine elevations.^[1] Being native to environments with cold winters, they produce a winter-resting bud (hibernaculum). There are three forms originating from Europe: P. vulgaris f. bicolor, which has petals that are white and purple; P. vulgaris f. albida, which has all white petals; and P. vulgaris f. alpicola, which has larger flowers.^[2] The taxonomic status of these forms is not universally recognised – see e.g. The Plant List.^[3]

Common butterwort is an insectivorous plant. Its leaves have glands that excrete a sticky fluid that traps insects; the glands also produce enzymes that digest the insects.^[4] This serves as a way for the plant to access a source of nitrogen, as they generally grow in soil that is acidic and low in nutrients, such as bogs.^[4][5] Insect capture is an adaptation to nutrient-poor conditions, and the plant is highly dependent on insects for nitrogen.^[6]

It has a generally circumboreal distribution, being native to almost every country in Europe as well as Russia, Canada, and the United States.^[5][7] It is generally found growing in places such as bogs, fens, alvars, and other areas with limestone bedrock and alkaline waters.^[5]

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  Flower from the side, Niitvälja bog, Estonia
• 
  Whole plant, Norway
• 
  Pinguicula vulgaris near Mývatn, northern Iceland

• USDA Plants Profile
• Forest Service Ecology