Ragged Nettlespurge (Jatropha macrorhiza) begins to bloom after the arrival of our summer monsoon rains here in southern Arizona. These native wildflowers are most common in the areas to the south of Tucson, especially in the lower northern foothills of the Santa Rita Mountains.

Ragged Nettlespurge can be recognized by its pink, 5-petaled flowers and palmately-lobed leaves with raggedly-toothed edges.

The entire plant is a bit soft and fleshy, and even though its appearance is quite different, Ragged Nettlespurge is actually closely related to the unusually flexible Sangre de Cristo or Heartleaf Limberbush (Jatropha cardiophylla).

While our other Jatropha species here in the Sonoran Desert have some uses in botanical medicine, Ragged Nettlespurge is best avoided as it is poisonous. Ragged Nettlespurge contains a powerful purgative oil and the poison Curcin, which is similar to Ricin. The entire plant is somewhat poisonous, but the seeds are by far the most dangerous part. Symptoms of acute poisoning are intense abdominal pain and bloody vomit and diarrhea after a delay of about an hour.

The poison Curcin, found in a number of Jatropha species, is a ribosome-inactivating protein currently being studied for its tumor killing properties. This Curcin is obtained from a tropical tree, the related Barbados Nut or Physic Nut (Jatropha curcas).