Palm trees in Firenze?

I find it so fascinating to see palm trees here in Europe.  Usually one would equate palm trees with the Caribbean or some hot climate country.  However, I have been warned that the temperatures rise to 40C in the hot summer months.  Just outside of my kitchen doors I can see a palm tree hovering over the next terrazzo....or is it piazza....let's say next door courtyard.  Anyhow last night  a couple of us went to see if we could buy some Annigoni tee shirts as this year commemorates 100 years of the Annigoni era.  Annigoni was a famous Italian painter that our Maestro studied under and there have been lots of activity and celebration.  We ended up having what is called 'apertivo' ...with a drink you get to eat from a yummy buffet table.  Perfect dinner for us Canucks as we can fill our plates as many times as we want.  For the frugal traveller being in Florence this would be ideal as most bars offer 'apertivo' from 6 onward.