I have a few mimosa trees I've noticed growing in my yard and I like them alot so I'm allowing them to grow instead of mowing them over as I have been doing. Now I'm noticing the little guys everywhere. I decided to bring one inside and see if I can get it to grow in a pot. Its been about a week and I've noticed this little tree isn't the same as the larger ones growing outside. The leaves are more broad with less on each branch and it has little balls that sprout with fuss like a normal mimosa tree bit these are on the underside. That hasn't even happened on my bigger trees that are outside so I assumed it shouldn't happen until the trees are much older than this one. What is this?