A numeric, geographic and structural analysis of the Hakea falcata group (Proteaceae)

Specimens placed earlier under Hakea falcata are shown to comprise four species: H. falcata, H. ulicina, H. erecta and H. cygna. Failure by previous authors to cite types, or the correct type, led to the placement of subsequently collected H. falcata specimens (sensu R. Br.) under H. ambigua in Australian herbaria. The relationships of the five taxa are explored phenetically using metric multidimensional scaling and cluster analysis. Flowers provide the best diagnostic characters for separating H. falcata and H. ambigua , while fruits and seeds are better for H. erecta and H. cygna. All species are endemic to SW Australia, except H. ulcina , which is endemic to SE Australia. Two subspecies of H. cygna are recognized, based on populations with disparate leaf morphology. Each taxon has a distinctive leaf anatomy with all but H. falcata highly sclerophyllous.