This was a very interesting erect, perennial euphorb, spotted by RT Hawke.

The one individual we saw had a somewhat small-bushy habit, about 3-4 dm high, with stiffly delicate and brittle-stems below, sparsely-spreading hairy and glaucous leaves, and tiny yellow cyathia with fringed white appendages. Initially it had a Chamaesyce gestalt to my eye, but it didn't key clearly to any species of Chamaesyce or Euphorbia in floras I consulted...so I tentatively (and playfully) referred to it as Chamaesyce RTae.

However, although there are perennial Chamaesyce that can have a non-prostrate mounding habit (e.g. Ch. parishii and Ch. polycarpa), this plant had more of a roughly ''inverted pyramid'' shape, reminiscent of some of the native CA Euphorbia species. Moreover, the cyathia here have 5 glands, and while the JM2 description of the genus Euphorbia states it can have 4-5 glands per cyathia, the description of genus Chamaesyce states it has 4 glands. So I'm tentatively posting these photos under Euphorbia sp..

While perusing CalPhotos for similar looking euphorbs, I found Jim Andre's posts of the recently described species Euphorbia jaegeri, to which the plant here appears to have affinities...in particular, the habitat where this plant was found was very much like that shown in Jim's images. Moreover, the common name given to that recently described species is ''Orocopia Mountains Spurge''....hhhmm? (For more info, scroll about 2/5 the way down this CNPS web page, or check this summary page from the CNPS Rare and Endangered Inventory web site.)

Update 3/2/13: ID confirmed as Euphorbia jaegeri by J. Andre, one of the authors of the species...see Aliso 30:1-4 (2012) for original description.