Magnolias are species of trees and woody shrubs that comprise the family Magnoliaceae. This is an ancient and relatively primitive group of dicotyledonous plants with fossil materials known from as early as the Upper Cretaceous. The magnolia family contains about 220 species in 12 genera, including the true magnolias (Magnolia spp.), with about 100 species.
Magnolias have seasonally deciduous or evergreen, oval-shaped, toothless leaves, arranged alternately on their twigs and branches. The flowers are bisexual, containing both male and female elements with three or more sepals and six or more showy petals. There are numerous stamens, arranged in a spiral fashion on the lower part of the elongate floral axis with numerous pistils spirally arranged above. The fruits are numerous, bright red or brown, and they hang with thread-like attachments from a semi-woody, cone-like structure derived from the floral axis.
The most widespread, tree-sized species in eastern North America is the cucumber tree (Magnolia acuminata) with greenish flower petals and extending over much of the eastern United States and extreme southern Ontario. The southern magnolia (M. grandiflora), sweet-bay (M. virginiana), and umbrella magnolia (M. tripetala) are more southern in their distributions and have white-petalled flowers. Species with relatively restricted southern distributions include the big-leaf magnolia (M. macrophylla), Ashe magnolia (M. ashei), Fraser magnolia (M. fraseri), and pyramid magnolia (M. pyramidata).
Magnolias are often cultivated as attractive trees and shrubs around homes and in parks. The native species most commonly used in horticulture is Magnolia grandi-flora, which is one of the famous shade trees of the southeastern United States. Although it is a less showy species than the southern magnolia, Magnolia acuminata is also commonly planted, especially in more northern regions. Asiatic species that commonly occur in horticulture include the star magnolia (Magnolia stellata), kobus magnolia (M. kobus), and saucer magnolia (M. soulangeana).
The tulip-tree (Liriodendron tulipifera) is another member of the magnolia family with a relatively wide distribution in southeastern North America. This species is commercially important for its straight, clear lumber, and as an ornamental tree.