Jatropha is a genus of about 175 species in the Euphorbiaceae. The majority of the species would be uninteresting to succulent collectors, but there are a few semi-succulent and pachycaul species worth a look. This particular species has some interesting characteristics -- see "Observations" for more info.
Growth Habit: Bushy, with greyish-brown stems and filiform (long and skinny) leaves. The side branches are much reduced and "knobby," which adds interest to the plant. It spreads by stolons (underground stems), so what look like bushes are really a group of separate plants.
Scientific name: Jatropha dioica Cerv.
Etymology: The generic (genus) name is from the Greek 'iatros' ("physician") and 'trophe' ("food"), referring both to the medicinal uses of some species in this genus, and cassava, which was formerly placed in this genus.
Taxonomy: It's been a wild ride for this species, described under no fewer than four genera, even before the 20th century! But in the end, the original description still stands. There are two subspecies, which differ only in the size of their leaves.
Distribution: Central Texas to New Mexico and south into Mexico.
Cultivation: This species definitely prefers full sun, and without it the stems may become elongated. During summer heat, it's reasonably tolerant of underwatering, but I've found it best not to let it go completely dry for more than a few days. In autumn, it will lose its leaves and look like a bunch of dead sticks. It needs no light at all during the winter, assuming it's kept dry.
Flowers: Appearing in spring, they are small, bell-shaped, less than 3/8" (8mm) long, light pink, and easy to miss. They are less complex
than the cyathia of Euphorbia species, which may mean that this genus is more "primitive."
Minimum temperature: According to one website, it's hardy down to 15 degrees Fahrenheit. That's not necessary for flowering, since I keep mine above freezing, and they grow well and flower freely.
Conservation Status: Not protected. Uncommon in cultivation.
Observations: This species has two common names, "Texas Leatherstem" and "Sangre de Drago."
I can vouch for the first, since I twisted this one into pretzel shapes and it had no effect -- once untwisted, it grew normally.
The second is Spanish for "Dragon's Blood," supposedly because the sap turns bright red when the stems are cut. That wasn't my experience, and the sap just stayed clear. Lest you accuse me of plant cruelty, the cut stems were potted up and began growing and branching shortly thereafter .
A more in-depth look at individual succulent species, a new one is added each week.
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