Those would be buds of one sort or another (branches or blooms). I have no experience with this species, but it apparently does branch higher up as well as at the base. Your plant looks amazing. I don't know what the cyathia (flowers) look like. This species looks a whole lot like hybrids of bupleurifolia, but evidently is its own beast.
I revisited the second volume of the Euphorbia Journal where they talk about this species and they do not mention cyathia at all. Nor was I able to find any kind of cyathia on a google image search. So if your plant is that big and it's never flowered, don't hold out a whole lot of hope that it's about to do so.
I am impressed by the size of your plant and would be most curious to see the cyathia look like, if any of these buds turn out to be blooms.