Hibbertia subvillosa (Dilleniaceae), a new Western Australian species segregated from H. striata

Abstract

The south-west Western Australian species Hibbertia striata (Steud.) K.R.Thiele was reinstated in 2017, segregated from the historically misunderstood H. huegelii (Endl.) F.Muell. Since that time, field work has shown that H. striata comprises two distinctly different morphotypes. Plants from the eastern (drier) edge of the range are consistently single-stemmed at the base and are obligate reseeders after fire and other disturbances, in contrast to a more widespread morphotype (which includes the type of H. striata), that is abundantly multi-stemmed from the base and is a resprouter after fire. The difference in habit is consistent, has been observed at multiple locations and is consistently associated with distinct (though subtle) differences in leaf indumentum and morphology. The two morphotypes have not been found growing in mixed populations, due to habitat differences. Field work has shown that they are narrowly sympatric and do not intergrade where they approach each other; for this reason, and the consistency of both morphotypes over a wide range, they are regarded here as distinct species. The reseeding taxon has a validly published name, H. huegelii (Endl.) F.Muell. var. subvillosa Domin, and this is raised here to species rank as Hibbertia subvillosa (Domin) K.R.Thiele & T.Hammer.