English Adjective haplobiontic (not comparable) (biology) Describing a plant or fungus that has either a haploid or a diploid phase (but not both) in its life cycle. That is, it lacks any alternation of generations. The algal ancestors of land plants were probably haplobiontic. Related terms haplobiont Anagrams LatinophobicWikiwand - on Seamless Wikipedia browsing. On steroids.