madder vs rubiaceous plant

madder and rubiaceous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
madder	Yes	No	Yes	No
rubiaceous plant	Yes	No	No	No

As nouns, rubiaceous plant is a hypernym of madder; that is, rubiaceous plant is a word with a broader meaning than madder:

madder: Eurasian herb having small yellow flowers and red roots formerly an important source of the dye alizarin
rubiaceous plant: any of numerous trees or shrubs or vines of the family Rubiaceae

Other hypernyms of madder include madderwort.

madder (noun)	rubiaceous plant (noun)
Eurasian herb having small yellow flowers and red roots formerly an important source of the dye alizarin	any of numerous trees or shrubs or vines of the family Rubiaceae

madder (verb)	rubiaceous plant (verb)
color a moderate to strong red