SCROPHULARIALES

order of dicotyledonous flowering plants, a division of the subclass Asteridae. Although most are herbaceous, some are shrubs, woody vines, or trees. Having wide distribution, they include weeds, ornamentals, and food plants. order of flowering plants that includes 12 families, about 750 genera, and approximately 10,000 species that are distributed on all the continents but Antarctica. About two-thirds of the plants are herbaceous (nonwoody); most of the rest are shrubs, and a few are woody vines or trees. The order includes food plants such as the olive and sesame, some ornamental herbs and shrubs, and many plants that are parasitic weeds. About two-thirds of the Scrophulariales occur in the tropics, one-third in the temperate regions of the world, and about 50 species in the Arctic. Most of the order's plants are perennials, although there are also some short-lived desert herbs and long-lived tropical trees. About three-fourths of the species in the order belong to just three large families: the figwort family (Scrophulariaceae), the acanthus family (Acanthaceae), and the gesneria family (Gesneriaceae). In size, the Scrophulariales cover a wide range, from the aquatic bladderwort (Utricularia olivacea), with stems that grow to about 10 cm (4 inches) in length, to the guayacan (Tabebuia guayacan), a tree that grows to about 50 m (164 feet) in height and 2 m in diameter. The smallest Scrophulariales fruits are the capsules produced by Micranthemum, less than 1 mm (0.04 inch) long, and the largest are those produced by the sausage tree (Kigelia pinnata), 90 cm (3 feet) long and sometimes weighing more than 7 kg (15 pounds). The Scrophulariales include aquatic and parasitic members. Among the aquatic plants are the bladderworts (Lentibulariaceae), of which the genus Utricularia is the only group of carnivorous plants to capture their prey (protozoans, crustaceans, worms, newly hatched fish) underwater. Two families of parasitic plants in the order, the broomrapes (Orobanchaceae) and figworts (Scrophulariaceae), contain all the known agriculturally important root parasitesi.e., parasitic plants whose roots are attached to the roots of their host by means of haustoria. Of the broomrapes, Aeginetia and Christisonia attack sugarcane, while the parasitic witchweeds (Striga and Alectra) of the figwort family attack corn (maize), sugarcane, rice, sorghum, peanuts (groundnuts), soybeans, and tobacco. Ornamental herbaceous plants are well represented in the order. Among its best-known garden and greenhouse plants are acanthus (Acanthus), African violet (Saintpaulia), snapdragon (Antirrhinum), calceolaria (Calceolaria), beard tongue, or penstemon (Penstemon), and gloxinia (Sinningia). Some ornamental shrubs in the order are also well known: cape fuchsia (Phygelius capensis), forsythia or golden bells (Forsythia), jasmine (Jasminum), lilac (Syringa), and privet (Ligustrum). The order also includes some of the showiest tropical ornamental trees, as, for example, the jacaranda (Jacaranda mimosifolia), the white-flowered Indian cork tree (Millingtonia hortensia), and the African tulip tree (Spathodea campanulata). In temperate regions, the catalpa (Catalpa) is a well-known tree. In their variety of form and colour, some flowers of the order rival the orchids. The olive ( Olea europaea), of the family Oleaceae, is native to the Old World and has been cultivated since antiquity for its edible fruit. Sesame (Sesamum orientale), of the family Pedaliaceae, also native to the Old World, is prized for its oil and for its seeds, which are used as flavourings and in confections. The foxgloves Digitalis lanata and D. purpurea are the sources of digoxin and digitoxin, respectively; these drugs are important in the treatment of irregular heart rhythms. Most members of the order have simple alternate or opposite leaves. Flowers are almost always complete and perfect (i.e., bisexual). Most flowers are pollinated by insects, or less commonly by hummingbirds and a few even by bats (sausage tree and Indian trumpet flower). Seeds are usually dispersed by wind, water, or animals. Most members of the order have capsular fruit, which may open by splits or pores in its wall. Other fruit types of the order are berries, samaras, and drupes. The number of seeds that a plant produces varies from the single seed of Globularia to the 333,000 seeds per plant produced by Boschniakia rossica of the broomrape family. Additional reading Johann Visser, South African Parasitic Flowering Plants (1981), an illustrated account of their biology, including members of the order Scrophulariales; John L. Fiala, Lilacs: The Genus Syringa (1988); three review articles on genera in the southeastern United States, with many references, in the Journal of the Arnold Arboretum: K.A. Wilson and C.E. Wood, The Genera of Oleaceae in the Southeastern United States, 40:369384 (1959); John W. Thieret, The Genera of Orobanchaceae in the Southeastern United States, 52(3):404434 (1971), and The Martyniaceae in the Southeastern United States, 58(1):2539 (1977).