Lilium is a genus of herbaceous flowering plants growing from bulbs, all with large prominent flowers. They comprise a genus of about 110 species in the lily family Liliaceae. Most species are native to the temperate northern hemisphere, though the range extends into the northern subtropics.
Lilies form an important group of flowering garden plants, and are important culturally and in literature in much of the world. Some species are sometimes grown or harvested for the edible bulbs. The species in this genus are the true lilies. Many other plants exist with "lily" in the common English name, some of which are quite unrelated to the true lilies.
Many species are widely grown in the garden in temperate and sub-tropical regions. Sometimes they may also be grown as potted plants. A large number of ornamental hybrids have been developed. They can be used in herbaceous borders, woodland and shrub plantings, and as a patio plant.
Some lilies, especially Lilium longiflorum, as well as a few other hybrids, form important cut flower crops. These tend to be forced for particular markets; for instance, L. longiflorum for the Easter trade, when it may be called the Easter lily.
Lilium bulbs are starchy and edible as root vegetables, although bulbs of some species may be very bitter. The non-bitter bulbs of L. lancifolium, L. pumilum, and especially L. brownii (Chinese; pinyin: bǎihé gān) and Lilium davidii var unicolor cotton are grown on a large scale in China as a luxury or health food, and are most often sold in dry form. They are eaten especially in the summer, for their perceived ability to reduce internal heat. They may be reconstituted and stir-fried, grated and used to thicken soup, or processed to extract starch. Their texture and taste draw comparisons with the potato, although the individual bulb scales are much smaller.
Classification of garden forms
Numerous forms are grown for the garden, and most of these are hybrids. They vary according to their parent species, and are classified in the following broad groups;
§ Asiatic hybrids (Division I). These are plants with medium sized, upright or outward facing flowers, mostly unscented. They are derived from central and East Asian species.
§ Martagon hybrids (Division II). These are based on L. martagon and L. hansonii. The flowers are nodding, Turk's cap style (with the petals strongly recurved).
§ Candidum hybrids (Division III). This includes hybrids of L. candidum with several other mostly European species.
§ American hybrids (Division IV). These are mostly taller growing forms, originally derived from L. pardalinum. Many are clump-forming perennials with rhizomatous rootstocks.
§ Longiflorum hybrids (Division V). These are cultivated forms of this species and its subspecies. They are most important as plants for cut flowers, and are less often grown in the garden than other hybrids.
§ Trumpet lilies (Division VI), including Aurelian hybrids (with aaL. henryiaa). This group includes hybrids of many Asiatic species, includingL. regale and L. aurelianse. The flowers are trumpet shaped, facing outward or somewhat downward, and tend to be strongly fragrant, often especially night-fragrant.
§ Oriental hybrids (Division VII). These are based on hybrids of L. auratum and L. speciosum, together with crossbreeds from several species native to Japan. They are fragrant, and the flowers tend to be outward facing. Plants tend to be tall, and the flowers may be quite large. An example is Lilium "Stargazer".
§ Other hybrids (Division VIII). Includes all other garden hybrids.
§ Species (Division IX). All natural species and naturally occurring forms are included in this group.
§ Many newer commercial varieties are developed by using new technologies such as in vitro pollination, ovary culture and embryo rescue.