What crested cactus is this??
it is a variegated crest of Euphorbia lactea, grafted. So, it is not a cactus. Cresting is a growth aberration, and so does not enter its Latin name. This aberration is propagated by by humans by grafting. See also:
Looks more like a cristate opuntia of some kind. MHO, Bill
Palmbob, is right; I jumped the gun, and gave my stock response to grafted Euph questions... mea culpa, mea culpa, mea maxima culpa
I have never seen "leaves" on a cristate euphorbia that look like these. Try 'austrocylindropuntia subulata crest' on bing and look at images. Sorry, this ID bothers me. Bill
It took me 9-10 photos of this form of E flanganii in my files to find a plant that did NOT have leaves like these... almost all the plants I have seen photos of leaves... most are a tad less leafy, or the leaves are smaller (these leaves on above plant are etiolated and most people expose their Euphorbias to more light so they are not so stressed). Anyway, here is a typical plant but the best close up I could find
I assume that like most of them, a Euphorbia would bleed milky say when wounded. Is that true for E. flanaganii?
I agree that milky sap would be definative. I also blew this photo up 400% to try to determine if the cross section of the leaves was cylindrical as they would be in A. subulata and as I thought they were. They are not so flanganii is probably correct. I'll blame it on my old eyes... Sorry for taking up your time. Bill
Milky sap would be strongly suggestive of Euphorbia, but not necessarily that species... and there are a lot of genera out there that have milky, toxic sap (Ficus comes to mind)