California Euphorbs of subgenus Esula

The California Esulas are so much easier than Texas Esulas. The hardest part is that there are so many more observations to go through (1896[Euphorbia] - 1067[Anisophyllum] - 47[Alectoroctonum] - 19[Poinsettia] = 763[Esula]). It's best to start out learning the species in this key: http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?key=9260. In addition to that, 5 other species are found in CA: E. characias, E. cyparissias, E. exigua, E. serrata, E. amygdaloides, and E. segetalis based on FNA and the observations on iNaturalist. Some of these may only be present in cultivation, but the observations were not clear enough to tell. The characteristics are given below:

E. characias: only species with hairy fruits; dichasial bracts connate (fused together) halfway or more; somewhat similar to E. virgata but larger and has glands without horns or much smaller horns.
E. cyparissias: like E. virgata, but narrower leaves.
E. exigua: annual with linear, entire leaves; imagine a linear-leafed E. peplus with acute apices.
E. serrata: like E. terracina but without horns on the glands and much deeper serrations on the leaves.
E. amygdaloides: like E. characias but with glabrous fruits; dichasial bracts obviously connate about half-way.
E. segetalis: like E. virgata but appearing stouter with thicker leaves, rougher fruits, and shallowly pitted seeds.

There are a few other commonly cultivated species that I need to learn just in case. Hopefully, I will get a chance to modify this into a more useful form and put it on the US Euphorbias project.

Other cultivated species:
E. epithymoides
E. lucida
E. x "Blue Haze"

Odd E. cf. virgata:
https://www.inaturalist.org/observations/12257377

Posted by nathantaylor nathantaylor, October 18, 2017 05:56

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