It's a home made one.You can see it in:" Camera Building,Repair and Mods"here on APUG,it"s in"Pix of your home-built camera etc.2" the thread's on page 5.
I kinda' agree about liking the cactus(actually called a Joshua Tree I'm told)better but the tangled tree limbs on the other tree picture caused a problem with dappled sunlight such that the semi stand development was strained to compinsate for it, I think(extreme contrast in the original subject)and as these are straight prints am thinking a little manipulation might be in order when reprinting.