The name lily is used chiefly for plants of the genus Lilium and related species but is applied also to plants of other families, e.g., the water lily, the calla lily, and especially the numerous species of the amaryllis family (often included in the Liliaceae) whose blossoms closely resemble the true lilies in appearance. Familiar among North American species of Lilium are the wood lily ( L. philadelphicum ), Turk's-cap lily ( L. superbum ), and Canada, or wild yellow, lily ( L. canadense ) of the East and the leopard lily ( L. pardalinum ), Washington lily ( L. washingtonianum ), lemon lily ( L. parryi ), and Humboldt's lily ( L. humboldtii ) of the West. Widely cultivated and often naturalized Old World species are the Madonna lily ( L. candidum ) and the martagon lily ( L. martagon ), also called Turk's cap lily. The white trumpet lily ( L. longiflorum ) of Japan includes the Easter, or Bermuda, lily (var. eximium ), which is the most popular greenhouse lily. The garden tiger lily is the Oriental species L. tigrinum, but many other lilies with spotted blossoms also bear the name.
Calochortus, mariposa or mariposa lily, is a genus of the lily family found in W North America. The white-blossomed sego lily ( C. nuttallii ) is the state flower of Utah. The day lilies, genus Hemerocallis [Gr., = beautiful for a day], native to Central Europe and Asia, are much cultivated and often found naturalized along roadsides. The name day lily is occasionally used for the Oriental plantain lily genus ( Hosta ) because it too has short-lived flowers. The glory, or climbing, lilies ( Gloriosa superba ) are plants of tropical Asia and Africa that climb by means of tendrillike leaf tips.
Many common wildflowers also belong to the lily family, e.g., the asphodel, brodiea, camass, Canada mayflower (see mayflower), dogtooth violet, greenbrier (see smilax), lily of the valley, Solomon's-seal, star-of-Bethlehem, and trillium.