| Family | Scientific Name | Common Name | Habitat | Distribution | Image |
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| Zygophyllaceae | Kallstroemia californica | | Mesquite savannas, other flat, sandy areas, especially disturbed. | Se., s., and w. TX, NM, UT, s. NV, and CA south to n. and c. Mexico. | |
| Zygophyllaceae | Kallstroemia hirsutissima | Carpetweed | Grasslands and scrub. | E. TX, NM, and s. AZ south to n. Mexico. | |
| Zygophyllaceae | Kallstroemia maxima | Greater Caltrop | Disturbed areas, dunes; native status uncertain, probably native in FL peninsula, but probably early introduced in more northern parts of our area from the Neotropics. | SC south to FL; West Indies; Mexico (Sinaloa and Tamaulipas) south through Central America to northern South America (Venezuela, Colombia). The native status of this species in the se. United States is uncertain; early collections from Charleston (Stephen Elliott) and Savannah suggest the probability of early introduction via ballast, at least north of the FL peninsula. | 
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| Zygophyllaceae | Kallstroemia parviflora | Texas Caltrop | Prairies, roadsides, other disturbed areas. | KS west to NV, south through TX, NM, and AZ to Mexico.; also introduced eastward, as in MS and nw. LA (MacRoberts & MacRoberts 2011a). | 
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| Zygophyllaceae | Kallstroemia pubescens | Caribbean Caltrop | Disturbed areas, apparently a waif, not collected in our area since 1898. | Native of tropical America. | 
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