1911 Encyclopædia Britannica/Milkwort

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MILKWORT, in botany, the common name for plants of the genus Polygala (natural order Polygalaceae), a large genus widely dispersed in temperate and tropical regions and represented by a few species in Britain. The common species, P. vulgaris, is a small wiry perennial found on heaths and in meadows throughout the British Isles. The stems are 2 to 10 in. long and bear narrow rather tough leaves and small, 1/6 to ⅓ in. long, white, pink, blue, lilac or purple flowers. The flowers (see fig.) are peculiar in form and arrangement of parts; they have five free sepals the two inner of which (b) are large petaloid and winglike, forming the most conspicuous part of the flower; the petals are united below with the sheath of the eight stamens forming a tube split at the base behind; their form recalls that of the pea family. The name Polygala is from the Greek πολύς, much, and γάλα, milk, the plant being supposed to increase the yield of milk in cows. Some species with showy flowers are known in cultivation as greenhouse, or hardy annual or perennial, herbs or shrubs. The root of P. Senega, snake-root, a North American species is officinal. Sea milkwort is the common name for Glaux maritima, a small succulent herb found on seashores and in estuaries in the British Isles; it belongs to the primrose order (Primulaceae).

Britannica Milkwort.jpg
After Berg & Schmidt, from Strasburger's Lehrbuch der Botanik, by permission of Gustav Fischer.
Polygala Senega.

A, Flower; a, small sepals; b, large sepals; c, keel, representing the anterior petal; d, its fimbriated edge; e, lateral petals.

B, The 8 stamens united into a sheath below; h, anthers (magnified).