This is a smaller and better behaved sibling of the large tree we cut down Tuesday (see picture below). The fruit is obviously beautiful and seems not to be of much interest to our (Eastern North American) wildlife. Though it seeds prolifically and seems to germinate well, we rarely (never?) observe seedlings beyond the dripline of the tree.
It's been there since at least 1990 and it's less then 20' by 20'. A member of the Rutaceae, it has a peculiarly chemical smell, not a nice citrusy smell, but unpleasantly pungent. This specimen grows in China Valley below the main path less than 100' in from the entrance. Bees and all manner of insects cover the flowers when it's in bloom; almost it's best trait!