 He acknowledges in his work "Larvae and Evolution" to have borrowed the idea of hybridogenesis from the well-known process of interspecific hybridisation that take place in plants.Hybrid plants generated from phylogenetically distant species can often give rise to new species if the hybrids become reproductively isolated from the progenitor populations.In one of his articles Williamson contends that

To prove the possibility of such hybridizations, Williamson claimed to have succeeded in 1990 in fertilizing sea squirt eggs with sperm from a sea urchin (a species from a different phylum).