The Cretan Flora
Crete has an extremely rich biodiversity. You get a good idea of how rich the biodiversity of Crete is by considering that Crete has about 300 more species and subspecies of plants (1.750 in total) as the whole of Britain that has about 1.450, all though Crete is 35 times smaller. The biodiversity of Crete is reflected - beside the total number of species - also in the number of endemic species (species that grow only in Crete and nowhere else in the world). On Crete there are about 160 endemic species and subspecies, which means that 9% of the plant species of Crete do not exist elsewhere in world.
The Cretan flora has adapted itself so as to resist the free grazing (a traditional practice in Crete for thousands of years) and human interventions. The plants have developed ways to resist grazing, like thorns or bad taste. There no large forest areas, like for example those in the region of Macedonia in north Greece or Epirus. Partly because of the grazing on Crete and also its climate. Thus Crete has some of the rarest bio-habitats in Europe, like e.g. those of the palm trees (Phoenix theophrasti).
The nature of Crete's flora with so many species that are endemic can be explained by the fact Crete is relative isolated broken away from mainland Greece and also the mountainous nature and overall morphology/geology, that creates many isolated habitats.