False Indigo

Amorpha fruticosa

Amorpha fruticosa with Celastrina butterfly photo © by Michael Plagens

Photographed along a sycamore-lined canyon on Pinal Peak, Gila Co., Arizona. June 2014. The butterfly is a Southwestern Azure, Celastrina echo.

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Amorpha fruticosa seed pods with Bruchidae, Acanthoscelides pallidipennis.  photo © by Michael Plagens

The bean pods have a warty surface and are each about 3.5mm long. Along side one of the pods is a bean weevil, Acanthoscelides pallidipennis (Bruchidae) which develops by tunneling out a bean.

FLOWERS: Numerous, small, dark purple flowers in a long, dense spike. Each of the small flowers has ten, conspicuous, yellow-orange stamens and just one dark purple petal.

LEAVES: Leaves are long-pinnately compound. The formula is odd, i.e. there is a terminal leaflet in addition to the pairs. Crushed foliage is malodorous.

SHRUB: Woody shrub with upper portions largely herbaceous. Upright stems often exceed two meters in height. May form thickets with many stems arising from ground level.

RANGE: False Indigo occurs sporadically in riparian habitats across Arizona growing mostly in clearings where there is a good underground water supply. This plant can also be found in sporadic locations across much of North America.

FRUIT: Small, indehiscent bean-pods with just a single bean. Glands dot the surface of the pod and are the source of noxious when touched. The seeds have been found to contain a class of chemicals known as rotenoids which may have application in treating tumors.


Fabaceae -- Bean Family

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False Indigo Bush, Amorpha fruticosa, photo © by Michael Plagens

Arizona Naturalist
Sycamore Canyons
The Flora of Arizona's Sycamore Canyons


Copyright Michael J. Plagens, page created 7 July 2010,
updated 10 Oct. 2015.