The Red Mangrove, Rhizophora mangle, is a species that does happen to be somewhat different from the Black Mangrove, Avicennia germinans. R. mangle takes on 95% salt water, and the other 5% gets stored throughout the tree. While A. germinans takes on 100% saltwater, and expels it through the leaves, to let rain wash it away.
Beside the facts that they're two different species AND one stores salt, while the other expels it, no. There aren't HUGE differences. They are still differences however.