Sunday, January 17, 2010

Sweet Gum

These seed balls on the ground indicate that there's a sweet gum close by. The globose fruits can be confused with those of the sycamore or the london plane tree.

The sycamore or london plane ball is an aggregate of hundreds achenes with tufts of hairs tucked inside (like the seeds on dandelions). When the balls break apart, the achenes are released.

The sweet gum ball is an aggregate of about 50 capsules with a seed or two in each one. As the balls mature, they become woody and holes open up between the two points of each capsule, allowing the release of seeds as the balls shake in the wind. The empty fruiting heads can still be found hanging on branches now. Some will remain on the tree throughout the winter. (The previous sweet gum post shows the unripe seed ball.)

The sweet gum typically has a single straight leader.

This species is a treat in the fall. From afar, the trees look like pastel rainbows.

Close up, the color varies from leaf to leaf, and even from one side of a leaf to the other.

These leaves were taken from one tree on the same day.


  1. Thank you!! Your blog is wonderful! You may have seen the post where I fell in love with Green-Wood: but I have very little (ok, zero) actual technical knowledge about trees. I'll have to keep visiting yours to learn about what I'm seeing. Great photos, too.

  2. Yay sweetgums! This is a great post - I just love these trees. Of course, it's never fun to step on the little gum balls, but their autumn color is totally worth the pain.