LILIACEAE, in botany, a family of Monocotyledons belong ing to the series Liliiflorae, and generally regarded as representing the typical order of Monocotyledons. The plants are generally perennial herbs growing from a bulb or rhizome, sometimes shrubby as in butcher's broom (Ruscus) or tree-like as in species of Dracaena, Yucca or Aloe. The flowers are with few exceptions hermaphrodite, and regular with parts in threes, the perianth which is generally petaloid occupying the two outer whorls followed by two whorls of stamens, with a superior ovary of three carpels in the centre of the flower; the ovary is generally three-chambered with a number of anatropous ovules or axile placentas. The fruit is a capsule splitting along the septa (septicidal), or between them (loculicidal), or a berry; the seeds contain a small embryo in a copious fleshy or cartilaginous endosperm. Liliaceae is one of the larger families of flowering plants containing about 2,700 species in 25o genera being approximately one-eighth of the Mono cotyledons; it is of world-wide distribution. It contains many useful plants (onion, leek, garlic) and garden plants (lily, tulip, hyacinth). The plants show great diversity in vegetative struc ture, which together with the character and mode of dehiscence of the fruit affords a basis for the subdivision of the family into tribes, eleven of which are recognized. The following are the most important tribes.
Melanthioideae.—The plants have a rhizome or corm, and the fruit is a capsule. Many are north temperate and three are repre sented in Britain, viz. Tofieldia, an arctic and alpine genus of small herbs with a slender scape springing from a tuft of narrow ensi form leaves and bearing a raceme of small green flowers ; Narthe cium (bog-asphodel), herbs with a habit similar to Tofieldia, but with larger golden-yellow flowers; and Colchicum, a genus with about 3o species including the meadow saffron or autumn crocus (C. autumnale). Colchicum illustrates the corm-development which is rare in Liliaceae, though common in the allied family Iridaceae. Gloriosa, well known in cultivation, climbs by means
of its tendril-like leaf-tips ; it has handsome flowers with recurved orange-red or yellow petals; it is a native of tropical Asia and Africa. V eratrum is an alpine genus of the north temperate zone.
Asphodeloideae.—The plants generally have a rhizome bearing radical leaves, as in asphodel, rarely a stem with a tuft of leaves as in Aloe, very rarely a tuber (Eriospermurn) or bulb (Bowiea). The flowers are borne in a terminal raceme, the anthers open introrsely and the fruit is a capsule, very rarely, as in Dianella, a berry. Asphodelus (asphodel) is a Mediterranean genus; Simethis, a slender herb with grassy radical leaves, is a native of west and southern Europe extending into south Ireland. Anthericum and Chlorophytum, herbs with radical often grass-like leaves and scapes bearing a more or less branched inflorescence of small generally white flowers, are widely spread in the tropics. Other genera are Funkia, native of China and Japan, cultivated in the open air in Britain; Hemerocallis, a small genus of central Europe and temperate Asia—H. flava is known in gardens as the day lily; Phormium, a New Zealand genus to which belongs New Zealand flax, P. tenax, a useful fibre plant; Kniphofia (red-hot poker), South and East Africa, several species of which are cultivated; and Aloe. A small group of Aus tralian genera closely approach the family Juncaceae in having small crowded flowers with a scarious or membranous peri anth; they include Xanthorrhoea (grass-tree or black-boy) and Kingia.
Allioideae.—The plants grow from a bulb or short rhizome ; the inflorescence is an apparent umbel formed of several short ened monochasial cymes and sub tended by a pair of large bracts.
The largest genus Allium has about 325 species-7 are British; Agapanthus or African lily is a well-known garden plant ; in Gagea, a genus of small bulbous herbs found in most parts of Europe, the inflorescence is reduced to a few flowers or a single flower; G. lutea is a local and rare British plant.