Characters.—Calyx and corolla both alike, coloured, regular, occasionally cohering in a tube. Stamens six, inserted into the sepals and petals; anthers opening inwards. Ovary superior, three-celled, many seeded; style one; stigma simple or three-lobed. Fruit succulent, or dry and capsular, three celled. Seeds packed one upon another in one or two rows; embryo with the same direction as the seed, in the axis of fleshy albumen, or uncertain in direction and position, occasionally very minute. Herbaceous plants, shrubs, or trees, with bulbs, or tubers, or rhizomes, or fibrous roots. Leaves narrow, with parallel veins, membranous, not articulated with the stem; either sessile or with a narrow leafy petiole.
Properties.—Not uniform. Mucilage, resinous matters, acrid volatile oils, and acrid extractive substances, are the organic principles to which the medicinal qualities of this order are chiefly referable. Their relative proportions, however, vary considerably in different species.
The fleshy bulbs are usually more or less acrid. Those of the genus Allium owe their acridity to a volatile oil (sulphuret of allylc) whose composition is C6H5,S (see vol. i. p. 253). Bundles of acicular crystals or raphides, usually considered to be phosphate, but by Schleiden declared to be oxalate, of lime are found in some of the cells of these bulbs.