conferva vs yellow-green algae

conferva and yellow-green algae both are nouns.

Word	Noun	Adjective	Verb	Adverb
conferva	Yes	No	No	No
yellow-green algae	Yes	No	No	No

As nouns, yellow-green algae is a hypernym of conferva; that is, yellow-green algae is a word with a broader meaning than conferva:

conferva: any of various algae of the genus Tribonema; algae with branching filaments that form scum in still or stagnant fresh water
yellow-green algae: any alga of the division Chrysophyta with its chlorophyll masked by yellow pigment

conferva (noun)	yellow-green algae (noun)
any of various algae of the genus Tribonema; algae with branching filaments that form scum in still or stagnant fresh water	any alga of the division Chrysophyta with its chlorophyll masked by yellow pigment