Taxonomy_of_the_coffee_plant

In order to classify the position of coffee in the Kingdom of the plants, one usually looks at close relatives within the
plant order or within the plant family. The order Gentiales consists of 5 families, among them the family Rubiaceae,
Gentianaceae and Apocynaceae.
Within the Rubiaceae, three subfamilies are distinguished. One of the subfamilies is Cinchonoideae, where one
known medicinal product is the Jesuit’s bark (or Cinchona bark). Those Cinchona trees or bushes have bitter tasting
bark, which was already discovered by the Quechua people of Peru. Therefore, they used to be cultivated to extract
quinines from its bark to treat malaria and fever or it was also used in bitter lemon. Nowadays quinines are
synthesized chemically.
Within the Rubioideae, one known plant is the noni tree (Morinda citrifolia or Indian mulberry), which is used in
traditional Chinese medicine. Noni juice contains many active phytochemicals that also was a reason for its
commercialization. Another important species is the genus Rubia, where some species were used as dyes, e.g.
common madder (Rubia tinctorum or dyer's madder) as a traditional coloring plant. The roots contain red colorant,
which were used already in ancient Roman times and the eponymous term Rubia is latin for red that gave the name
to the family.
Within the third genus Ixoroideae, Gardenia is closest related genus to coffee. This genus consists of small,
evergreen shrubs and because of its heavily fragrant, white flowers, plants of this genus are widely used in gardens
in warm climates. Within the Ixoroideae 15 tribes are distinguished, whereof one is Coffeeae. The tribe Coffeeae in
turn contains 15 genera, whereof one is Coffea. Within the genus Coffea 125 species of coffee are included,
whereof only 2 species are used economically.
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