Flora of North America species comparison

The vernacular name, cucumber-tree, alludes to the resemblance of the follicetum to the young fruit of cucumber. It is the only magnolia species in the flora that occurs naturally in Canada.

Studies of Magnolia acuminata have failed to reconcile the nature of variation in this widespread species. In an attempt to settle differences in variation patterns, J.W. Hardin (1954) recognized four infraspecific taxa in M. acuminata. Later (1972, 1989) Hardin abandoned his earlier views for a more conservative stance, stating that variation in M. acuminata lacked any consistent pattern or geographic correlation. This is the view taken here–no infraspecific taxa are accepted for M. acuminata at this time. Its flowers are normally greenish and glaucous or sometimes yellow to orange-yellow, less showy than those of other magnolias in the flora. In southern areas, trees with yellow to orange-yellow flowers (originally described by Michaux as M. cordata) occur in North Carolina, Georgia, Alabama, and perhaps elsewhere, together with trees that bear normal greenish flowers. Both filiform and flagelliform trichomes occur on the leaves; cylindric trichomes also occur.

Magnolia acuminata is of value to horticulturists because no other species of the genus has yellow tepals. Magnolia acuminata contains major quantities of xanthophyll lutein-5,6-epoxide and, in smaller amounts, acarotene-5,6-epoxide. Although this carotenoid occurs randomly throughout populations of M. acuminata, often it is masked by chlorophyll and not visibly expressed. Sometimes the carotenoid pigment shows through, as in the hybrid M. acuminata × M. denudata 'Elizabeth'. In that cross the M. acuminata parent tree was a nondescript plant with greenish flowers; yet out of this hybrid came 'Elizabeth', a stunning plant with light canary yellow flowers, a result completely unexpected. A thorough field study of M. acuminata is clearly warranted, and further investigation of the carotenoid flower pigments is needed to clarify the taxonomy of this widespread tree.

The largest known tree of Magnolia acuminata, 29.6m in height with a trunk diameter of 1.26m, is recorded from a specimen cultivated in Waukon, Iowa (American Forestry Association 1994).

The Cherokee and Iroquois tribes used Magnolia acuminata, largely the bark, as an analgesic, antidiarrheal, gastrointestinal aid, anthelmintic, toothache remedy, and for various other uses (D.E. Moerman 1986).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Magnolia grandiflora (a hexaploid) is highly variable, especially the leaves, which range from glabrous to densely red-brown felted on the abaxial surface. It is the only magnolia species in the flora with free stipules, and the inner spathaceous bract is unique among Magnolia taxa in the flora. Curled filiform trichomes occur on the abaxial leaf surface. In the wild, hybrids with M. virginiana (a diploid) have been reported but not confirmed by the present author. The compatibility of these taxa is well known from the Freeman hybrid, a highly sterile tetraploid growing at the U.S. National Arboretum in Washington, D.C. In crosses using the hexaploid M. grandiflora, this parent is dominant and nearly masks the other parent.

Magnolia grandiflora is an escape, and it naturalizes in the tidewater area of Virginia and locally elsewhere beyond its natural range in the southeastern United States. It ranks among the noblest of North American broadleaved trees and is cultivated widely in the United States and in many other countries. A large number of cultivars have been introduced to horticulture.

Southern magnolia (Magnolia grandiflora) is the state tree of both Louisiana and Mississippi.

The largest known tree of Magnolia grandiflora, 37.2m in height with a trunk diameter of 1.97m, is recorded from Smith County, Mississippi (American Forestry Association 1994).

The Choctaw and Koasati tribes used the bark of Magnolia grandiflora as dermatological and kidney aids (D.A. Moerman 1986).

(Discussion copyrighted by Flora of North America; reprinted with permission.)