Systematics of the Xanthosia pilosa complex (Apiaceae: Hydrocotyloideae)

Abstract

Xanthosia pilosa Rudge is a common shrub found ineastern Australia. The species complex displays a wide range of variation inleaf and inflorescence morphology which has resulted in the application ofnumerous species names and its informal division into numerous variants in New South Wales. As part of a revision of the genus, the history of the speciescomplex is reviewed and the morphology of the numerous variants, examined bothin the field and herbarium, is discussed.Xanthosia pilosa sens. lat. is here divided into fourspecies: two new species (X. scopulicola J.M.Hart & Henwood and X. stellataJ.M.Hart & Henwood) are described and illustrated, a substitute name(X. ternifolia J.M.Hart & Henwood) is providedfor the illegitimate X. tasmanica Gand., andX. pilosa s.s., which remains a polymorphic species inwhich further segregation of variants is not recommended. A key toXanthosia species in eastern Australia is provided.