Periwinkle, in zoology, a pectinibranchiate gasteropod shell, of the genus littorina (Ferus-sac). The shell is univalve, with a few spiral whorls, the horny operculum made up also of a few spiral turns; the tentacles are two, the two eyes being at the base on the outside; the mouth is at the end of a proboscis, the gills comb-shaped, and the foot moderate, with a groove on the lower surface. L. littoralis (Linn.), which abounds on the English and French coasts, is round, brown, longitudinally streaked with blackish; the shell is thick, and without pearly lining; it is oviparous, and lives in the lowest zone of seaweed between low and high water marks. L. Uttorea is preeminently the periwinkle of the British coast; immense quantities are brought to the London market, and form a considerable article of food for the poorer classes; after being boiled, the animal is picked out of the shell with a pin.
Periwinkle. - 1. Littorina littorea. 2. Littorina rudis.
The rough periwinkle (L. rudis, Mat.), from the ocean washing the shores of Europe, frequents a higher zone of seaweed; this is ovo-viviparous, and the young acquire a calcareous shell before they are excluded, for which reason the species is not eaten. There are many other species, all marine, inhabiting almost all parts of the globe, living on the rocks between the tide marks; three species are very common on the coast of New England, of small size, and probably never eaten.
Periwinkle (Lat. permnca, probably from per, about, and vincire, to bind, from its use in forming chaplets; old Eng. pervenlce and per-mnke), a common name for species of vinca, which in this country are quite as frequently called myrtle and running myrtle. The genus vinca (Lat. vinculum, a band) belongs exclusively to the old world; it is placed in the apo-cynacece, or dogbane family, which includes the oleander, allamanda, and other showy flowers; some species have weak stems and are trailing, others are erect; while most have evergreen leaves, there is a herbaceous one in cultivation; the flowers have a somewhat bell-shaped tube, with a flat spreading limb having five broad oblique segments; stamens five, inserted on the middle or upper part of the tube; ovaries two, connected at the top by a single style, and becoming in fruit two elongated many-seeded pods, the seeds without the tuft frequently met with in the order. The best known species is the common or lesser periwinkle, V. minor, a native of Europe, and wild in England, though supposed to be introduced; it is very common in gardens, where its weak stems spread upon the ground, taking root at the joints; these long stems are sterile, the flowers being borne upon short erect stems, and solitary in the axils of their leaves, appearing in early spring, light blue, and in pleasing contrast to the smooth, dark green evergreen leaves.
The large periwinkle, V. major, is much larger in all its parts; its leaves are also evergreen and shining, but have a fringe of minute hairs upon the margins; the erect flowering stems are a foot or more high, and the flowers quite large. This is not so common as the preceding, as it is less hardy, and in our northern gardens, while the roots usually survive, the foliage is killed unless in a sheltered place. Both these species have produced several varieties, there being those with white and double flowers, and of both kinds there are forms with variegated leaves. Though very old-fashioned, they are useful plants, and especially the variegated kinds, planted in vases, baskets, and flower stands, where their long stems can hang over the edge; they are sometimes used as edgings to beds, and to form a carpet beneath shrubbery; the smaller species grow well in the shade, and may be used to cover the ground where grass will not flourish. As the stems root so freely, the plants may be divided indefinitely. The herbaceous species (V. herbacea), from Hungary, flowers later than the foregoing; as its name indicates, its stems die down every winter; in manner of growth it is similar to the others, and being less rampant it is preferred for planting on rockwork.
A greenhouse species, V. rosea, from the West Indies, but called Madagascar periwinkle, has erect stems, somewhat woody at base, persistent veiny leaves, and large axillary, showy flowers, which are rose-colored, white, or white with a red eye; it is an abundant bloomer, and is often used in the borders as a bedding plant.
Common Periwinkle (Vinca minor).
Madagascar Periwinkle (Vinca rosea).