The Rosidae
Family Overview - The Fabales
Caesalpiniaceae - the Senna Family
Diversity:  The Caesalpiniaceae includes about 150 genera with ca. 2,200 species, both herbaceous and - mostly - woody - see tribal classification.

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.
 

flower
plants
leaf
young ovary
fruit

 More information on the Caesalpiniaceae

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