Actually, the Genus Sophora has been replaced with Styphnolobium though, for sentimental reasons - and the fact that most people in the nursery trade still do - I like to stick with its older name. The common name is Japanese Pagodatree or Japanese Scholartree. It's one of the loveliest street trees, as it has flowers in the summer, persistent edamame-like pea pods (it's in the Fabaceae family) and adequate yellow fall color.
You see this tree all over New York City. Usually they reach about 40-50 feet in height, with a caliper of 10-12". However, in the Jardin du Plantes in Paris, I saw an 18th Century specimen that was just a wee bit larger:
The water bottle gives you an idea of how wide the trunk is - my best estimate was 5' or so.
The plaque dated the specimen as planted in 1747 :
I looked a little ridiculous to the other people strolling the gardens - taking dozens of photos of this tree, mouth agape. In my bad French, I tried to explain to one Frenchman how unusual it is to see this tree at this size. He was mildly, politely, impressed.