gametophyte
Concise Oxford English Dictionary © 2008 Oxford University Press:
gametophyte /gəˈmiːtə(ʊ)fʌɪt/
▶noun Botany (in the life cycle of plants with alternating generations, e.g. ferns) the gamete-producing phase (typically haploid), which produces the zygote from which the sporophyte arises.
– derivatives
gametophytic adjective.
gametophytic adjective.
'gametophyte' also found in these Oxford entries:

