White crown of Thorns ( euphorbia milii )

Ah, looks good too. I almost commented about there being a white variety less often seen and here you have it too. :-)

GT:

Euphorbia milli has many hybrids. There's yellow, white, pink and various shades of red...also with small to huge flower bracts. I know this because it's a small to large (to 7 feet) common landscape shrub here in San Diego.

I remember seeing these a lot when I lived in Encino CA back in the early 80's.
I was amazed the first time that I saw them. Another plant that amazed me was Jade. I had a thick hedge of it separating me from my neighbor.

Mikec:

Yes, Jade grows enormous here in San Diego, CA. I've seen large specimens in California 12 feet tall.