umbellifer (umbelifer)

[ Umbelliferæ (um-be-life-rē), n. pl. [NL. (A. L. de Ju ieu, 1789), fem. pl. (sc. L. plantæ, plants) of umbellifer: see umbelliferous. An order of plants, of the cohort Umbellales, known as the parsley family. It is distinguished by a two-celled ovary forming in fruit a cremocarp consisting commonly of two dry one-celled and one-seeded mericarps or achenes, separating from each other at maturity, and hanging from the top of a slender axis or carpophore. It includes about 179 genera with about 1,400 species, cla ed in 9 tribes, of which Hydro cotyle, Mulinum, Sanicula, Echinophora, Ammi, Seseli, Peucedanum, Caucalis, and Laserpitium are the types. They are natives chiefly of north temperate regions, especially numerous in Europe and Asia, reaching the arctic zone and mountains within the tropics, also numerous in the temperate parts of South America, South Africa, Australia, and New Zealand. Most of the species are herbs with di ected alternate leaves of many ternate or pinnate leaflets, the petiole commonly dilated into a sheathing base. The flowers are small, usually white or yellow, and borne in simple or compound umbels, generally furnished with a row of narrow bracts forming an involucre or involucel. Each flower consists commonly of five small imbricated petals, as many stamens in the bud, and an ovary crowned with an epigynous two lobed disk which rises into two conical stylopodia, each tipped with a distinct filiform style. The fruit is commonly traversed by canals (oil-tubes or vitte ) filled with liquid or gummy oil of a highly penetrating and characteristic odor. The genera resemble one another closely, and are distinguished mainly by the ridges, the oil-tubes, and the commi ure or inner face of the fruit; each carpel bears five primary ridges ( juga ), and frequently also five intermediate secondary ones, the channels ( valleculæ ) between them often containing oil-tubes. Many are proterogynous, or mature their pistils earlier than the stamens, thus securing cro -fertilization. The order is one of strongly marked properties; many umbelliferous plants contain a poisonous, acrid, watery liquid, especially the hemlock (see also Conium, Cicuta, Enanthe, and Æthus a ). Many species yield stimulating gum-resins, as asafetida, asadulcis, galbanum, opopanax, and gum ammoniacum (see also Ferula, Thapsia, and Laserpitium ). Others contain a carminative aromatic oil, and furnish condiments, as anise, dill, caraway, coriander, and cumin. From another group these principles are nearly absent, and the stem or leaf becomes edible, as parsley, celery, and samphire, or the root, as the carrot, parsnip, and skirret. Others are of great medicinal repute, as fennel and species of Eryngium and Archangelic a. The order is remarkable for its little resemblance or close relationship to any other except the Araliaceæ, which are, however, readily distinguished by their usually fleshy fruit, often of more than two carpels. Perhaps no other order is so free from variation or from exceptional forms, although in a few genera the characteristic habit is greatly disguised as in Eryngium, where the umbels are replaced by compact heads; Hydro cotyle, with roundish undivided leaves; and Xanthosia, with broad and showy white invo lucres.