A section of a stem of L. a. africana. The swollen
section to the left is a domatium showing the entry
slit created by the resident ants, Petalomyrmex phylax.
Arrows point to worker ants. Source.
Early in childhood, we learned that the plants and animals around us are discrete entities with definite boundaries. A dog might have fleas, but fleas and dogs are separate and distinct individuals. With our increased familiarity with symbioses—especially those of the obligate sort—have come many instances where "separate" individuals can seemingly survive only as part of a functioning association. Here is yet another example.
For more than twenty-five years, Doyle Mckey, now a professor in ecology, University of Montpellier II, France, has been studying one species of tree, Leonardoxa africana africana (Fabaceae or Leguminosae)—known locally as the bush-boer bean. Likely you've never seen one of them as they are found only in a narrow strip of humid coastal rain forest in southern Cameroon. This particular tree is a myrmecophyte, i.e., an ant-plant. (For those who relish words as we do, myrmecophyte is from the ancient Greek myrmeco, "ant" and phyton, "plant." Myrmecophyte is not to be confused with myrmecophile, a general term for any organism that lives in association with ants, or with the Myrmecophila, a genus of myrmecophytic orchids.)