|Laurus nobilis flowers and leaves|
The order includes 85-90 genera from seven families of trees and shrubs. Most of the species are tropical and subtropical, though a few genera reach the temperate zone. The best known species in this order are those of the Lauraceae (for example bay laurel or Laurus, cinnamon or Cinnamomum, avocado or Persea, and Sassafras), and the spice bush or Calycanthus of the Calycanthaceae.
The earliest lauraceous fossils are from the Cretaceous. It is possible that the ancient origin of this order is one of the reasons for its highly diverged morphology. Indeed, at present no one trait is known which would unify all the members of Laurales. This used to cause much argument among botanists about the correct limits of the order. The presently classification is based on recent molecular and genetic analysis.