Dictionary.com
definitions

rubiaceous

[roo-bee-ey-shuh s]

adjective

belonging to the Rubiaceae, the madder family of plants.
Compare madder family.

Origin of rubiaceous

1825–35; < New Latin Rubiace(ae) name of family (Rubi(a) genus name (Latin rubia madder, akin to ruber red1) + -aceae -aceae) + -ous
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for rubiaceous

rubiaceous

adjective

of, relating to, or belonging to the Rubiaceae, a widely distributed family of trees, shrubs, and herbaceous plants that includes the coffee and cinchona trees, gardenia, madder, and bedstraws

Word Origin for rubiaceous

C19: from New Latin Rubiaceae, from Latin rubia madder, from rubeus red
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012