Please help with an identification for this if possible.

I will post a 2nd photo showing the whole plant which is a dense tangled mass of slender stems about 3' tall. This was blooming at the LA Arboretum in August.

 

2nd photo of the whole plant.

 

My first thought is that's quite pretty. Second thought is - looks like something in the Rubiaceae. Haven't been able to confirm that yet, though.

 

It looks quite like Gomphostigma virgatum or River Star.

 

Can't be! That's not in the Rubiaceae!

Just kidding - does look very much like what you suggested, mplant.

 

Sorry about that, Daniel. I did feel guilty about offering something in another family.
River Star (nice common name) seems to be hardy here in Vancouver. A small one came through last winter in a planter in my garden.

 

No need to feel guilty - I don't mind being wrong.

 

Looks like a very good suggestion. It was in an area adjacent to the South Africa section so that would fit, also right for bloom time, opposite narrow leaves, 4-petal flowers. I think that may be it.