allogamy vs cross-fertilization

allogamy and cross-fertilization both are nouns.

Word	Noun	Adjective	Verb	Adverb
allogamy	Yes	No	No	No
cross-fertilization	Yes	No	No	No

As nouns, cross-fertilization is a hypernym of allogamy; that is, cross-fertilization is a word with a broader meaning than allogamy:

allogamy: cross-fertilization in plants
cross-fertilization: fertilization by the union of male and female gametes from different individual of the same species

Other hypernyms of allogamy include cross-fertilisation.

allogamy (noun)	cross-fertilization (noun)
cross-fertilization in plants	interchange between different cultures or different ways of thinking that is mutually productive and beneficial
	fertilization by the union of male and female gametes from different individual of the same species