This cactus lives in an interesting place.
A spot in Lotusland where
you can stand in the middle of the
street and see an incredible example
of parallel evolution. On one side
of the street are Cactus, from the
deserts of the Americas. On the other,
there are plants that most would
mistakenly call cacti too. However,
if you look a little closer, you
will see some subtle differences.
For example, thicker thorns rather than
thin "needles" and a sticky white sap,
which incidentally is at least a little
poisonous. These plants are Euphorbia.
Their most common relative, one that you would probably
recognize, is the Poinsettia. They are from
the arid areas of Africa. Although they
appear similar to Cacti, they have
been separated by a half a world for
most of their evolutionary history.
An interesting statement on the influence
of environment in evolution.