haplobiontic

Describing a life cycle in which either the sporophyte or gametophyte generation is lacking. For example, in the green alga Chlamydomonas the plant is haploid and the diploid condition is represented only by the zygospore, which gives rise to haploid zoospores immediately on germination (see haplontic). In diatoms the plant is diploid and arises directly by the fusion of gametes formed by the sporophyte generation (see diplontic). Compare diplobiontic.