Taxonomy
of Flowering Plants - LECTURE
NOTES - Spring, 1998
Hugh
D. Wilson - rm. 306,
Butler Hall
23 March 1998
The Rosidae
Family Overview - The Fabales
Caesalpiniaceae - the Senna Family
Diversity: The Mimosaceae
includes about 150 genera with ca. 2,200 species, both herbaceous and -
mostly - woody.
Distribution: Worldwide,
but mostly tropical and subtropical. We have 8 genera and 37 species
in Texas including common, weedy herbs, such as Chamaecrista
fasciculata and forest trees, such as Gleditsia
triacanthos, the honey locust.
Floral structure:
Significant features:
Leaves of this family tend to be pinnately compound.
Floral zygomorphy involves a 'papilionaceous' or butterfly-like aspect
that reflects the size and configuration of the 5 petals. The uppermost
petal, usually the largest and known as the standard or banner petal, is
flanked by two 'wing' petals, thus producing the 'butterfly-like' aspect.
Local Cercis canadensis (red bud of floodplain
forests - now in flower); plants, flower with small standard petal
flanked by two wing petals (note reproductive parts more or less enclosed
by the two, separate, lower petals), and fruits - note unusual simple leaves:
The local prairie senna (Chamaecrista fasciculata
- below) shows a typical flower with red stamens (ovary is green),
a typical (even pinnate) leaf structure and the distinctive marker for
the Order Fabales, a legume.
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flower
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plants
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leaf
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young ovary
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fruit
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More information on the Caesalpiniaceae
Return to Lecture
Notes, the Botany
201 homepage, or the Rosidae
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