CARYOPHYLLIDAE

subclass of flowering plants belonging to the class Magnoliopsida. The subclass consists of three orders, Caryophyllales, Polygonales, and Plumbaginales, although the vast majority of its members are found in the order Caryophyllales. The order Polygonales comprises a single family, Polygonaceae, the buckwheat, or dock, family, with about 30 to 40 genera and about 1,000 species. Consisting mostly of herbs and some trees, shrubs, and vines, Polygonaceae is prevalent in north temperate areas. The leaves of this family alternate along the stem, and the stipules are usually united into a sheath that surrounds the stem at the base of the leaf petiole. The inflorescences are generally cymes or racemes, and the individual flowers are bisexual with a superior ovary consisting of three united carpels at the base of which is a single ovule. Although small, the order consists of popular vegetables and cultivated ornamentals. One of the best known vegetables in the order is rhubarb (Rheum cultorum), a hybrid cultivated for its edible leafstalks; sorrel (Rumex acetosa), is used as a green vegetable in salads, and buckwheat (Fogopyrum esculentum) is grown for the flour produced from it. Seaside grape (Coccoloba uvifera) develops an edible fruit used in making jellies. Redshank, or willowweed (Polygonum persicaria), is a common weed in the United States but is grown as an ornamental in many parts of Europe. Plumbaginales contains a single family, Plumbaginaceae, or the leadwort family. Although common throughout the world, members of the order thrive along seashores and in other saline environments. The family consists of perennial herbs, shrubs, and leaves. The leaves are simple and entire and without stipules; they form rosettes at the base of the stem or grow in an alternate pattern on branched stems. The flowers are regular with a superior ovary and form racemes, cymes, or panicles. The largest genera, Plumbago (leadwort) and Limonium, are popular garden plants. Caryophyllales is by far the largest and most diverse order and is discussed separately. The Editors of the Encyclopdia Britannica subclass of dicotyledonous flowering plants, the vast majority of whose members are in the family Caryophyllales (q.v.).