As Craig recognized, our mystery seeds last week were from the white leadtree, Leucaena leucocephala.
Originally from Central and South America, the white tree has been planted throughout the world. It has been used for forage and wood.
Unfortunately the characteristics that make it attractive - being hardy and fast growing - also make it a potential weed. It is already on the invasive list in many countries.
The leadtree produces many white, round flowers throughout the spring. They turn brown once they have been pollinated.
White leadtrees produce many seed pods, which can look messy hanging on the tree.
Do leadtrees grow where you live?
What do you think of them?