phytology vs algology

phytology and algology both are nouns.

Word	Noun	Adjective	Verb	Adverb
phytology	Yes	No	No	No
algology	Yes	No	No	No

As nouns, algology is a hyponym of phytology; that is, algology is a word with a more specific, narrower meaning than phytology:

Other hyponyms of phytology include mycology, pomology, palaeobotany, paleobotany, phycology, pteridology.

phytology (noun)	algology (noun)
the branch of biology that studies plants	the branch of botany that studies algae