Rubiaceae - the Coffee or Madder Family
Diversity: Mostly herbs in temperate floras with a few shrubs and, in the tropics, some trees - a large and important family of about 600 genera and ca. 10,000 species. This Family is the source of coffee (Coffea arabica - northern Africa), the anti-malarial quinine (Cinchona officinalis - Andean South America), and a red natural dye taken from the 'madder' plant - Rubia tinctorium.
Distribution: Worldwide with maximum diversity in the tropics. We have 19 genera and 62 species in Texas.
Significant features: This is one of the few flowering plant families that carries the following set of key characters:
Number of androperianth parts varies between four
five, depending on the genus and - with the exception of epigyny - the
floral structure is typical of the Asteridae. While rare,
some taxa produce zygomorphic corollas. Stipules, usually present
between the petioles of the opposite leaves and the whorled phyllotaxy
of some taxa is believed to be a result of enlargment of the stipules
a leaf-like structure. Fruit structure is variable, but often
or drupaceous. A coffee 'bean' is actually a 'half-pyrene' in
the Coffea fruit is a 2-seeded drupe.
Coffea arabica - (left) with versatile anthers and strange drupe-like fruit and Rubia tinctorium (right) - with whorled leaves
Local bluets - Houstonia pusilla (or Hedyotis crassifolia):
citrifolia from Hawaii - full diversity of the family is
in tropical taxa. This one shows large interpetiolar stipules, a
pentamerous corolla and fusion of ovaries from separate flowers to
a multiple fruiting structure. See the family
overview from the University of Hawaii for more examples.
More information on the Rubiaceae