Aaron, my observation is that around canberra S. behriana has leaves that stick up like the one in your photo, rather than fS. Sericea that tend to be flat lying. The terminal leaflet in sericea is also suppose to be longer than others, while in behrina they are suppose to be the same but I don't know how reliable this is. The reliable test is to look at the hairs - I think I have this the right way around if the hairs are basically a straight structure it is behriana but if it is like a T shape but with one arm of the T much longer than the other it is sericiea - you may have to go and have a closure look