We have multiple of this tree growing on my college campus and I cannot figure out what type of tree it is. I've never seen anything like it. It has a light green leaf that always grows on top of a darker green one with a flower/fruit forming on top of that. Thanks for your help!
This is a member of the linden family, or Tilia. This tree is probably Tilia Cordata or the little leaf linden which is native from Europe to western Asia.
A favourite with landscape architects in Europe in the 17th and 18th century and in North America from 1950 to the late 1970's due to the sweet smelling flowers and modest size when mature (~65' 20M) this tree is no longer planted widely due to these issues:
- significant litter problem, something is always dropping year round
- subject to aphids who excrete sticky sap on vehicles nearby
- attractive to bees and yellow jacket wasps
- not very tolerant of drought which results in leaf scorch
- tendency to have multiple leaders which can produce split trunks
- japanese beetles can completely defoliate the tree in a bad year
The North American tilia, the basswood, is a better choice for some locations if you have moister soil.