Botany Photo of the Day

While planning my trip to the southwest USA last year, I briefly entertained the notion of crossing the border into Mexico to see this species in the wild. Though time didn't permit, I was glad at least to see these in cultivation at Huntington Botanical Garden.

Creeping devil is native to sandy, coastal areas of Baja California Sur. Eruca refers to “caterpillar” (one who eats caterpillars is an erucivore); the rationale for the name should be readily apparent.

The Wikipedia entry for Stenocereus eruca provides some interesting details about the plant, including its growth rate and pattern. The article also cites a reference that suggests Stenocereus eruca is the “most extreme case of clonal propagation in the cactus family”. Intriguingly, while the species does seem to have an extremely high ratio of clonal propagation vs. sexual recruitment, the clones have a high rate of diversity within populations: Clark-Tapia et al. 2005. Clonal diversity and distribution in Stenocereus eruca (Cactaceae), a narrow endemic cactus of the Sonoran Desert. Am. J. Bot. 92: 272-278. With a high rate of clonal propagation (in fact, the authors allude to not observing any seedlings in the few years of the study), one would expect the populations to have low genetic diversity. The authors speculate that reproduction via sexual recruitment occurs only episodically in bursts during favourable years. Unfortunately, as the authors note, ecological studies carried out over short spans of time can miss events such as these and draw incomplete conclusions – another example in favour of investing in long-term ecological studies.