Thorny questions

Richard L. Brown moth at RA.MSSTATE.EDU
Mon May 15 10:04:38 CDT 2000

The Blackbelt of Mississippi-Alabama has a mixture of habitats including
prairie, scrub, and oak-hickory forest. Thorny shrubs/trees, eg. Robinia,
Zanthoxylum, Bumelia, and  Maclura pomifera are more abundant in the
Blackbelt than elsewhere in MS.  Thorny shrubs are characteristic of
savannas and dry areas elsewhere, e.g., Guanacaste, Costa Rica.  John Kaye,
in his 1974 disseratation at Louisiana State Univ., suggested that the
abundance of thorny plants in the Blackbelt was related to the presence of
Pleistocene browsers (mastodon, peccary, sloth) in this area.

I would be interested in obtaining feedback, suggestions of references or
other mailing lists that could help answer these questions.

1)  Why are thorny plants more abundant in savannas and areas like the
Black Belt than elsewhere?
2)  If thorns were an adaptation against Pleistocene and earlier browsers,
what kept these browsers from going into habitats where plants were less
thorny?  Why wouldn't other plants outside savannas develop thorniness as a
defense against these browsers.

And for botanists or others, Maclura pomifera (Osage Orange) has been
considered to have an original distribution in southern Oklahoma and
Arkansas and eastern Texas, with the present expanded range attributable to
Amerinds who had utilitarian purposes for the tree.  Mississippi had six
tribes of Amerinds, including the Choctaw who living in the Blackbelt as
well as outside this region.  What evidence is available to document
dispersal of Maclura by Amerinds into the Blackbelt from western areas?
Why is the tree concentrated in the Blackbelt and not common in bottomlands
and other areas that have rich soils to support this tree?  I'm looking for
information to support an idea that Maclura in Mississippi may represent a
disjunct population from the western population, similar to our Dalea
(prairie clover) and other plants disjunct from the Central Great Plains.

Richard L. Brown
Mississippi Entomological Museum
Box 9775
Mississippi State, MS 39762
phone: (662) 325-2085
fax: (662) 325-8837
e-mail: moth at

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