Flora of North America species comparison

The disposition of Magnolia macrophylla and its close relative M. ashei has been perplexing since M. ashei was described. Some investigators have treated them as geographic varieties or subspecies, and this has some questionable merit. In the foliar state M. macrophylla is hardly, if at all, distinguishable from M. ashei, but in other morphologic details of flower and fruit, they are readily distinguished. They also differ in the floral odors, which are distinct and chemically different (L.B. Thien et al. 197). Magnolia macrophylla and M. ashei are allopatric. Magnolia macrophylla is a much larger, usually single-trunked tree of the piedmont with a wider distribution, larger leaves, more stamens, larger stipules, and both filiform and flagelliform trichomes on the leaves. The follicetum is nearly globose-ovoid, with more pistils and larger seeds. Magnolia macrophylla produces the largest leaves and flowers of any species of the genus.

In Arkansas Magnolia macrophylla was known from a single disjunct locality in Clay County, where only two trees were recorded in 1981 (R.B. Figlar 1981). A survey in 1995 failed to locate the species in the same site.

This handsome tree is occasionally cultivated. A close relative, M. dealbata Zuccarini, occurs in Mexico.

The largest known tree of Magnolia macrophylla, 32m in height with a trunk diameter of 53 cm, is recorded from Daniel Boone National Forest, Tight Hollow, Kentucky (American Forestry Association 1994).

The Cherokee tribe used Magnolia macrophylla, mainly the bark, as an analgesic, antidiarrheal, gastrointestinal aid, respiratory aid, and toothache remedy (D.E. Moerman 1986).

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

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.)