periwinkle, in botany: see dogbane.

periwinkle, any of a group of marine gastropod mollusks having conical, spiral shells. Periwinkles feed on algae and seaweed. They are found at the water's edge; out of water, they resist drying by closing themselves into the shell with a horny plate. The edible European species, called the common periwinkle, has become well established on the Atlantic coast of North America. About 12 other species are found on rocky beaches of both the Atlantic and the Pacific coasts. Periwinkles are classified in the phylum Mollusca, class Gastropoda, order Mesogastropoda, family Littorinidae, genus Littorina.

In zoology, any of some 80 species (family Littorinidae) of widely distributed, chiefly herbivorous shore snails. Periwinkles are usually found on rocks, stones, or pilings between high- and low-tide marks. The common periwinkle (Littorina littorea), the largest northern species, may grow to 1.5 in. (4 cm) long. It is usually dark gray and has a solid spiral shell. Introduced into North America circa 1857, it is now common on Atlantic coasts. All periwinkle species are a favourite food of many shorebirds.

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Periwinkle is...Flora and fauna

• Periwinkle (mollusc)
• A regional term for the gravel-encased larva of the Caddisfly
• Periwinkle (plant), two related genera:
• Catharanthus (Madagascar periwinkles)
• Vinca (European periwinkles)
• Periwinkle (color), a pale shade of indigo, from the flower colour of VincaOther
• A character from the television show Blue's Clues