I have two BRTs but they are growing quite differently from each other. I think there is a variation in the species, right?
Yes, there are 2 found variations.
Most BRTs in the USA come from Florida and are cuttings or results from air-layers; these are not grown from seeds, and most found in America will never bloom, and the thorns are few or inexistent.
The one I have as bonsai in Brazil is from seed, and a little different: the bark looks rough like the one in
@Rodrigo 's post above (n# 28 I think), is full of thorns, and it flowers every Spring.
The leaves are of course the same, and obviously they love the Brazilian weather, BUT...
If left in full sun in high summer (temps 95F and above), even with its leaves closed to protect themselves, damage can happen to them, and it can drop leaves.