The Collaborative International Dictionary of English v.0.48:

Magnolia \Mag*no"li*a\, n. [NL. Named after Pierre Magnol,
   professor of botany at Montpellier, France, in the 17th
   century.] (Bot.)
   A genus of American and Asiatic trees, with aromatic bark and
   large sweet-scented whitish or reddish flowers.
   [1913 Webster]

   Note: Magnolia grandiflora has coriaceous shining leaves
         and very fragrant blossoms. It is common from North
         Carolina to Florida and Texas, and is one of the most
         magnificent trees of the American forest. The sweet bay
         (Magnolia glauca)is a small tree found sparingly as
         far north as Cape Ann. Other American species are
         Magnolia Umbrella, Magnolia macrophylla, Magnolia
         Fraseri, Magnolia acuminata, and Magnolia cordata.
         Magnolia conspicua and Magnolia purpurea are
         cultivated shrubs or trees from Eastern Asia. Magnolia
         Campbellii, of India, has rose-colored or crimson
         flowers.
         [1913 Webster]

   Magnolia warbler (Zool.), a beautiful North American wood
      warbler (Dendroica maculosa). The rump and under parts
      are bright yellow; the breast and belly are spotted with
      black; the under tail coverts are white; the crown is ash.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Magnolia macrophylla
    n 1: large deciduous shrub or tree of southeastern United States
         having huge leaves in dense false whorls and large creamy
         flowers tinged purple toward the base [syn: large-leaved
         magnolia, large-leaved cucumber tree, great-leaved
         macrophylla, Magnolia macrophylla]