Ant Acacia (Vachellia allenii). This tree is endemic to Costa Rica and is endangered. It has ants living on the tree in a symbiotic relationship, protecting the tree from other insects. (1338k)
Here are the pictures of Ant Acacia (Vachellia allenii) with links to the pages on which they appear, links to the full sized picture, and the description of the picture with links to the entry in iNaturalist (inaturalist.org)
All pictures are © Dr. Günther Eichhorn, unless otherwise noted.
Costa Rica Nature
Dr. Günther Eichhorn Travel Website
Soaring website