The Rosidae
Family Overview - The Fabales
Caesalpiniaceae - the Senna Family
Diversity:  The Caesalpiniaceae includes over 170 genera with ca. 2,000 species, both herbaceous and - mostly - woody - see tribal classification.

Distribution:  Worldwide, but mostly tropical and subtropical.  We have 10 genera and 51 species in Texas including common, weedy herbs, such as Chamaecrista fasciculata and forest trees, such as Gleditsia triacanthos (distribution), 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 - see map and also Cercis occidentalis); 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

Return to Lecture Notes, the Biology 301 homepage, or the Rosidae page