Source : Webster's Revised Unabridged Dictionary (1913)

Rubiaceous \Ru`bi*a"ceous\, a. [L. rubia madder, fr. rubeus
   red.] (Bot.)
   Of or pertaining to a very large natural order of plants
   ({Rubiace[ae]}) named after the madder ({Rubia tinctoria}),
   and including about three hundred and seventy genera and over
   four thousand species. Among them are the coffee tree, the
   trees yielding peruvian bark and quinine, the madder, the
   quaker ladies, and the trees bearing the edible fruits called
   genipap and Sierre Leone peach, besides many plants noted for
   the beauty or the fragrance of their blossoms.