Cleomaceae (Capparaceae)

©The World Botanical Associates Web Page
Prepared by Richard W. Spjut
Dec 2004, Feb 2011, Sep 2022

     Wislizenia has been generally regarded monotypic, W. refracta Engelm., which included four subspecies, all  have been considered annuals as indicated in Shreeve and Wiggins, Vegetation and Flora of the Sonoran Desert (1964). However, three species are recognized by Gordon C. Tucker in Flora North America (Vol.7, 2010) based on differences in habit of the plant in which the shrubby habit of W. fruticosa is included under W. palmeri, while Greene (1906) had long ago recognized 10 species.

     We collected samples of Wislizenia in April 1990 from a sand dune along the Gulf Coast in the southern part of Baja California Norte near Buffeo.  They were identified Wislizenia fruticosa Greene based on the shrubby habit as evident in photo shown below where occurring near its type locality, Calamajué, based on a specimen collected by Brandegee.  It was not clear whether the type for W. palmeri, an earlier name, represented a woody plant; thus, our plants were assigned the name W. fruticosa, because the epithet implies that the species was shrubby and because we collected it near the type locality.  Although W. fruticosa has been regarded as a synonym of W. palmeri, and this earlier name was previously accepted on this website in Feb 2011, upon further review, W. fruticosa appears distinct based on the plant's habit and fruit characters mentioned in Greene's revision. In Greene's key, the two species appear in a couplet together and are distinguished as follows:

“Valves pyriform, closely and sharply lineolate and with some elongated reticulation,
the summit crowned with a circle of 5 spreading mammiform tubercles”            W. fruticosa

“Valves long, subturbinate-pyriformj, strongly striate, near the summit fenestrate-reticulate, the summit with a circle of long connivent tubercles”                                               W. palmeri

The plants at Buffeo are not even close to being annual.  They have woody stems with roots very deep in sand.  They appear much like Isomeris arborea and are likely to be passed by for this species if it were not for the distinctive fruit, which is a flattened triangular-shaped camarium, 2 celled, with one seed in each cell.  Greene (1906), in his introduction, noted that W. fruticosa was the exception in the genus in its "shrubby" habit; the remaining species all annuals; however, W. palmeri is described by Preston & Vanderpool in the Jepson Manual (2nd ed., 2012.) as a short lived perennial. The collection site was observed during the 1990's to have become increasing utilized by Off-Road-Vehicles.



Wislizenia fruticosa
Gulf Coast near near Buffeo (Buteo)
and Isla San Luis, Baja California, Mexico
Spjut & Marin 11627 (BCMEX, US)
April 1990.  Habit of the plant on left, general habitat shown on right.
Similar to bladderpod in habit and foliage, but notably differs in the bilobed, peanut-like fruit (camarium).

Wislizenia fruticosa

Spjut & Marin 11627 (BCMEX, US)



Wislizenia palmeri

Near margin of playa, Palen Lake, Sonoran Desert. CNPS Field-Based Rare Vegetation Sampling/Mapping Workshop in East Riverside County, Feb 5–6, 2011.


Wislizenia palmeri

Image by Sue Carnahan. On SEINet. Reportedly taken in Mexico, Sonora, Guaymas, Alluvial plain near San Jose de Guaymas. 27.98982 -110.83968 WGS84. CC BY-NC (Attribution-Non-Commercial). Presented here for comparison of fruits for the two species shown.


Trees and Shrubs of Kern County (Jan 2013, Sep 2022)

Wislizenia palmeri A. Gray 1873.  Type in HUH ("possible" type, high resolution image!, possibly annual). Not in Kern  County. Palmer's spectacle fruit. Plants annual, perennial, or shrubs, The shrub habit similar to bladderpod (Isomeris arborea). The fruit separates at maturity into its carpellary units, each containing a single seed.  California locations are reported from sand dunes near a dry lake northeast of Desert Center in Riverside Co., and in Anza Borego, San Diego Co. In Arizona reported from the Organ Pipe National Monument, and in Mexico, in state of Sonora. The shrub species, W. fruticosa Greene (holotype US, high resolution image!), is known only from Baja California, Mexico; it flowers in the spring.  In Kern County, we have the annual W. refracta Englemann ssp. californica (Greene) S. Keller that flowers in late summer to fall; it is endemic to the Valley.  The typical subspecies is much more widely distributed in summer rainfall areas of the southwest. The FNA (Vol. 7) treats the three varieties in California as species.


Greene, E. 1906. Revision of the genus Wislizenia.  Proceedings of the Biological Society of Washington 19(28): 127–132.

Preston, R.E. & S. S. Vanderpool 2012.  Wislizenia refracta subsp. palmeri, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=53419, accessed on September 03, 2022

Spjut, R. W. 2022. Jackass Clover, Wislizenia (Cleomaceae), Rare Species in Kern County and Elsewhere.. CNPS Kern Chapter Newsletter, Mimulus Memo, September issue.

Tucker, G. C. 2010. Wislizenia. FNA 10: 213–214.  Three species: W. palmeri, W. californica, W. refracta.