Mitragyna is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of trees in the Rubiaceae

Rubiaceae

The Rubiaceae is a family of flowering plants, variously called the coffee family, madder family, or bedstraw family. The group contains many commonly known plants, including the economically important coffee , quinine , and gambier , and the horticulturally valuable madder , west indian jasmine ,...

 family. Members of this genus contain antimalarial and analgesic

Analgesic

An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....

 indole alkaloids. Species of this genus include Mitragyna ciliata, Mitragyna ledermannii, Mitragyna parviflora, Mitragyna speciosa, Mitragyna stipulosa. and Mitragyna inermis. The Rubiacae is the fifth largest family of flowering plants by number of genera, and the fourth or fifth largest by number of species.