Clarification of species boundaries within the Ptilotus royceanus Benl (Amaranthaceae) group

Abstract

The Ptilotus royceanus Benl species group comprises P. royceanus, P. mollis Benl and P. maconochiei Benl. Ptilotus royceanus as currently circumscribed has a disjunct distribution, occurring on the border of Western Australia and the Northern Territory and in central Queensland to the east of the range of P. maconochiei. Ptilotus mollis is endemic in Western Australia. We critically re-examine the morphological boundaries of these species and provide evidence that all Queensland collections currently included in P. royceanus are referable to P. maconochiei. Updated descriptions and a key are given for all three species.