Parasexually produced hybrids between female and male plants of Griffithsia tenuis C. Agardh, a red alga.

Somatic cell fusion between vegetative cells of a male and a female isolate of Griffithsia tenuis, a marine red alga, has been obtained. Hybrid cells have been isolated and they have regenerated new plants. Almost all these hybrid plants made reproductive structures. In nearly half these cases the first 3-10 cells of the hybrid filament produced reproductive structures chracteristic of the tetrasporic (diploid) phase rather than the sexual (haploid) phase of the life cycle of this alga. However as these filaments continued to grow, cells further along the filament began to produce sexual, either female or male, reproductive structures. The observations suggest that the production of tetrasporangial branches does not require the fusion of male and female nucleic; rather, male and female nucleic remaining separate, act in concert to produce these structures, and in subsequent cell divisions the nuclei of one sex may be left behind allowing the nuclei of the remaining sex to direct the production of sexual branches.