pollinium vs pollen

pollinium and pollen both are nouns.

Word	Noun	Adjective	Verb	Adverb
pollinium	Yes	No	No	No
pollen	Yes	No	No	No

As nouns, pollen is a hypernym of pollinium; that is, pollen is a word with a broader meaning than pollinium:

pollinium: a coherent mass of pollen grains (as in orchids)
pollen: the fine spores that contain male gametes and that are borne by an anther in a flowering plant

pollinium (noun)	pollen (noun)
a coherent mass of pollen grains (as in orchids)	the fine spores that contain male gametes and that are borne by an anther in a flowering plant