Rubia cordifolia vs madderwort

Rubia cordifolia and madderwort both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rubia cordifolia	Yes	No	No	No
madderwort	Yes	No	No	No

As nouns, madderwort is a hypernym of Rubia cordifolia; that is, madderwort is a word with a broader meaning than Rubia cordifolia:

Rubia cordifolia: perennial East Indian creeping or climbing herb used for dye in the orient
madderwort: any of numerous trees or shrubs or vines of the family Rubiaceae

Other hypernyms of Rubia cordifolia include rubiaceous plant.

Rubia cordifolia (noun)	madderwort (noun)
perennial East Indian creeping or climbing herb used for dye in the orient	any of numerous trees or shrubs or vines of the family Rubiaceae