Genetic and morphological evidence supports the hybrid status of Adenanthos cunninghamii (now Adenanthos × cunninghamii)

Abstract

Hybridisation is common among plants and is considered to be an important process in evolution. However, there is much debate as to the role of hybridisation in conservation, particularly whether species of hybrid origin should be protected. In general, conservation policy allows for the protection of hybrids and hybrid progeny if they are shown to be taxonomically distinct, stable and capable of self-perpetuation, and naturally produced. The rare species Adenanthos cunninghamii was suspected to be a hybrid between putative parents, Adenanthos sericeus and Adenanthos cuneatus, as it only occurs where these species co-occur and it displays intermediate and variable morphology. Genetic analysis of A. cunninghamii and the two putative parent species was consistent with this species being a hybrid between A. sericeus and A. cuneatus. Direct analysis of diagnostic loci and phenetic analysis indicated that A. cunninghamii was not genetically uniform and was genetically intermediate between the putative parents. A. cunninghamii is not a distinguishable taxon, morphologically or genetically, and does not produce offspring with morphology within the taxonomic description of the species, thus the species does not satisfy the criteria for protection of hybrids and listing as a rare species in Western Australia.