Okay, I sound like a geezer but...when I was a kid this was the Hall of Flowers and the Arboretum was called just that, or Strybing Arboretum if you wanted to get technical. Now it is the "San Francisco Botanical Garden at Strybing Arboretum". Whatever the name, one of my favorite places. Did you know they have a botanical library?
I did a search of photos in the S.F. Library's collection here. Apparently the building was constructed between 1959 and 1961.
It seems to me the tree that used to be right in front really obscured the structure. It's only in the past few years I've noticed the building, although I have been in it many times over the years for sales and events.
I can't remember when this blue plastic fence thing went in.
The building has grown (ha ha) on me over the years.