The Victorian box (Pittosporum undulatum) is one of San Francisco's most common trees, and small white flowers of the tree are out all over the city - as usual in late February/early March. They aren't conspicuous visually, but they have the strongest fragrance of any common tree in San Francisco, and when they emerge en masse, they can fill entire blocks with their orange blossom-like perfume. It's a smell that I associate strongly with San Francisco, as I've never seen any city that has this tree more densely than SF. One of my first memories of San Francisco was walking down Hyde Street, preparing to turn on Pine to walk downtown to my first job, and smelling the Victorian Box trees around the corner before I saw them!
The flowers of this Australian native are followed by groups of small green fruits, which they turn yellowish, then orange, and finally break open dropping a sticky mess on whatever's below. As a result, the tree has dropped in popularity a bit, with some trying the sweetshade tree (Hymenosporum flavum) instead. Sweet shade is another Australian tree