This week, we continue our series on the native trees of the Chicago area with a look at basswood trees (Tilia sp.), also known as linden trees.  These trees are found throughout the Northern Hemisphere in North America, Europe, and Asia and there are around 30 known species in the world.  Basswood trees are known for their thick canopies, heart-shaped leaves, and fragrant flower clusters. There are around 30 known species of basswood trees...