Alien Species
The plants in this photograph are all hardy species, capable of flourishing in arid conditions, but they ought not to be growing in Morocco - or in Spain, the Canary Islands, St Helena... and dozens of other disparate parts of the world.
The prickly pear is common throughout the warmer drier parts of America and is believed to originate in Mexico.
The sisal plant probably started out in the same region.
Both plants have been spread by man, both having been useful to us in the pre-petroleum, pre-coca-cola era.