lignosae vs ligneous plant

lignosae and ligneous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
lignosae	Yes	No	No	No
ligneous plant	Yes	No	No	No

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

lignosae: a category in some early taxonomies
ligneous plant: a plant having hard lignified tissues or woody parts especially stems

Other hypernyms of lignosae include woody plant.

lignosae (noun)	ligneous plant (noun)
a category in some early taxonomies	a plant having hard lignified tissues or woody parts especially stems