The Rosidae
Family Overview - The Fabales
Mimosaceae - the Mimosa Family
Diversity: The Mimosaceae
includes about 40 genera with ca. 2,000 species, both herbaceous and -
mostly - woody.
Distribution: Worldwide,
but mostly tropical and subtropical with a focus on dry regions, as indicated
by the large and typical Genus Acacia.
We have 10 genera and 54 species in Texas including the 'mimosa tree' (Albizia)
that grows on campus and sometimes escapes cultivation, mesquite (Prosopis),
plus 'sensitive' herbs (leaves move when touched) of the genera Mimosa
and Schrankia.
Floral structure:
Significant features:
Leaves of this family tend to be bipinnately compound.
While the actinomorphic flowers are
distinctive relative to other beans, they are usually quite small.
The most distinctive floral feature of the Mimosaceae is the inflorescence,
which is usually a spherical head of these small, regular flowers with
the stamens well excerted from the (often) sympetalous corolla and the
filaments taking on an attractive function.
Local Acacia smallii; plant, inflorescences,
and fruits - note bipinnate leaves:
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Local herbs of the Mimosaceae:
Neptunia lutea (right) and Mimosa nuttallii
(left)
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The local mesquite (Prosopis glandulosa - below)
shows bipinnate leaves but only 1 or rarely two pairs of pinna (compounded
leaflets) - and a linear (non-spherical) inflorescence - this species,
according to Correll and Johnston is "probably the commonest 'legume' in
Texas" and, given habitat destruction in the state and concurrent invasive
advance of this species from the South, this statement is supported as
time passes.
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branch
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leaves
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flowers
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fruits
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More information on the Mimosaceae
Return to Lecture
Notes, the Botany
201 homepage, or the Rosidae
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