I saw these two plants at the Cactus Garden at Kapi'olani Community College in Honolulu and right away thought they were giant Colletia. Well, they're not. The first of these I do actually have the ID for. It's Adenia globosa, in the Passifloraceae family of all things. But I don't know what this one is, and I'd like to know. It's similar in size to the Adenia. I didn't see flowers, but it does seem that they grow at the ends of the branches and not at the base of the spines or nodes, the way Colletia and Adenia do.
Not that this is going to help any, but I did get a photo of the measurement from a different individual of the plant in question.
I'm so excited, particularly to see the very few photos of flowers and fruits that came up on the query. Thank you. Many of the photos look just like it, and the ones that look less like it look like an out-of-focus photo I have of a new shoot seemingly emerging from the rock. Interesting too is a tree photo labelled Euphorbia stenoclada ssp. stenoclada at madabotanik.com. There are several Euphorbia photos on that page; there doesn't seem to be a way to jump to the name without scrolling through them all. There are three photos, one ssp. ambatofinandrahana (no close-up) and the other two ssp. stenoclada, starting at the 41st photo in the series. Common name Silver Thicket.
