Senna armata (S. Watson) H. Irwin & Barneby

Desert Senna
Fabaceae (Pea Family)


Desert or spiny senna is a rounded, glabrous, much-branched shrub growing to 6' tall. The yellow-green striate stems are leafless throughout much of the year, but when the leaves are present, they contain 2-4 pairs of distantly-spaced ovate leaflets that are ± opposite and sessile, and the leaf rachis is elongated and enlarged at the apex to form a weak spine.  The inflorescence is a terminal raceme to 6" long with 1-2 flowers in each leaf axil, and the five yellow to salmon-red petals are slightly less than 1/2" in diameter, irregularly obovate and somewhat veiny.  The fruit is a dehiscent pod which is straight, linear to lanceolate, cylindrical and 3/4" to 1-1/2" long with few seeds. Senna is common in sandy and gravelly washes and open flats in both deserts below 3000' and blooms from April to May.  It was formerly recognized as Cassia armata. These pictures were taken in the East Mojave and at Anza-Borrego Desert State Park.

Click here for Latin name derivations: 1) Senna 2) armata.
Pronunciation: SEN-na ar-MAY-ta.
Click here for Botanical Term Meanings.