I
In botany, any of various plants of the genus Vinca of the dogbane family .
The lesser periwinkle ( V. minor ), which has small lilac-blue flowers, is a dependable, trailing, evergreen perennial that is native to Europe and has become widespread over much of eastern North America. The greater periwinkle ( V. major ), with larger leaves and larger purplish-blue flowers, is native to continental Europe and has become naturalized in England. Alkaloids derived from the periwinkle plant have had some success in inhibiting cancer growth.
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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 с 1857, it is now common on Atlantic coasts. All periwinkle species are a favourite food of many shorebirds.
Periwinkles ( Littorina )
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