Roystonea vs liliopsid genus

Roystonea and liliopsid genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Roystonea	Yes	No	No	No
liliopsid genus	Yes	No	No	No

As nouns, liliopsid genus is a hypernym of Roystonea; that is, liliopsid genus is a word with a broader meaning than Roystonea:

Roystonea: a monocotyledonous genus of West Indian feather palms
liliopsid genus: genus of flowering plants having a single cotyledon (embryonic leaf) in the seed

Other hypernyms of Roystonea include monocot genus.

Roystonea (noun)	liliopsid genus (noun)
a monocotyledonous genus of West Indian feather palms	genus of flowering plants having a single cotyledon (embryonic leaf) in the seed