These are quite beautiful spiders, as jumping spiders are, and big enough that you can spot them from a few feet away. I've been trying to get a photo of one, but they are quick and wary. I haven't yet been successful.
When I was scouting around some milkweed today I found, on three plants in one small area (and one on a lawn chair), another jumping spider. Very plain, brown (cryptic) with a quite bright white mask over the eyes.
I've been doing some searching around, and the best guess I have so far is that this is a member of the genus Ghelna, the only trouble being that this is a genus of ground-dwellers, which means both that one wouldn't expect to find them living up in the milkweeds, and that there aren't as many pictures of them as there are of other jumpers. So, I don't really know, and the picture isn't great (these too are wary and quick). The spider is about the same size as the Brilliant jumper, but very plain except for the mask, and give the impression of dark brown or dark grey and fuzzier than the Brilliant. This one was in a little folded leaf shelter--the others I saw were free-ranging on the leaves of the plants.