LILIACEAE

The lily family, Liliaceae, consists of about 254 genera and about 4075 known species of flowering plants within the order Liliales. They are monocotyledonous, perennial, herbaceous, often bulbous geophytes. Plants in this family have evolved with a fair amount of morphological diversity despite genetic similarity. Common characteristics include large flowers with parts arranged in threes: with six colored or patterned petaloid tepals (undifferentiated petals and sepals) arranged in two whorls, six stamens, and a superior ovary. The leaves are linear in shape, with their veins usually arranged parallel to the edges, single and arranged alternating on the stem, or in a rosette at the base. Most species are grown from bulbs, although some have rhizomes. First described in 1789, the lily family became a paraphyletic "catch-all" (wastebasket) group of petaloid monocots that did not fit into other families and included a great number of genera now included in other families and in some cases in other orders. Consequently, many sources and descriptions labeled "Liliaceae" deal with the broader sense of the family.

The family evolved approximately 52 million years ago during the Late Cretaceous to Early Paleogene eras. Liliaceae are widely distributed, mainly in temperate regions of the Northern Hemisphere and the flowers are insect pollinated. Many Liliaceae are important ornamental plants, widely grown for their attractive flowers, and involved in a major floriculture of cut flowers and dry bulbs. Some species are poisonous if eaten and can have adverse health effects on humans and household pets.

The Liliaceae are characterized as monocotyledonous, perennial, herbaceous, bulbous (or rhizomatous in the case of Medeoleae) flowering plants with simple trichomes (root hairs) and contractile roots.

The flowers may be arranged (inflorescence) along the stem, developing from the base, or as a single flower at the tip of the stem, or as a cluster of flowers. They contain both male (androecium) and female (gynoecium) characteristics and are symmetric radially, but sometimes as a mirror image. Most flowers are large and colorful, except for Medeoleae. Both the petals and sepals are usually similar and appear as two concentric groups (whorls) of 'petals', that are often striped or multi-colored, and produce nectar at their bases. The stamens are usually in two groups of three (trimerous) and the pollen has a single groove (monosulcate). The ovary is placed above the attachment of the other parts (superior). There are three fused carpels (syncarpus) with one to three chambers (locules), a single style, and a three-lobed stigma. The embryo sac is of the Fritillaria type.

The fruit is generally a wind dispersed capsule, but occasionally a berry (Medeoleae) which is dispersed by animals.

The leaves are generally simple and elongated with veins parallel to the edges, arranged singly and alternating on the stem, but may form a rosette at the base of the stem.

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