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Australian Systematic Botany Australian Systematic Botany Society
Taxonomy, biogeography and evolution of plants
RESEARCH ARTICLE

Morphological and molecular evidence supports the recognition of a new subspecies of the critically endangered Pityrodia scabra (Lamiaceae)

Kelly A. Shepherd A C , Andrew Perkins A , Joel Collins B , Margaret Byrne A and Kevin R. Thiele A
+ Author Affiliations
- Author Affiliations

A Science Division, Department of Environment and Conservation, Locked Bag 104, Bentley Delivery Centre, WA 6983, Australia.

B Eco Logical Australia, PO Box 237, West Perth, WA 6005, Australia.

C Corresponding author. Email: kelly.shepherd@dec.wa.gov.au

Australian Systematic Botany 26(1) 1-12 https://doi.org/10.1071/SB12009
Submitted: 7 March 2012  Accepted: 14 November 2012   Published: 12 April 2013

Abstract

Taxonomic delineation of closely related taxa can be difficult, particularly in regions such as southern Western Australia where a highly diverse flora exhibits complex patterns of subtle morphological variation and genetic structuring and where some taxa have highly disjunct populations. A combined approach utilising highly variable, non-coding chloroplast gene regions and morphological data is used here to help delimit cryptic taxa in the rare Western Australian species Pityrodia scabra A.S.George. The species comprises disjunct populations over 400 km of the Western Australian wheatbelt from near Wyalkatchem, Southern Cross and Lake Lefroy. Morphological features such as leaf phyllotaxy, calyx size and indumentum vary among the populations and provide some evidence for cryptic taxa. Phylogenetic analyses based on cpDNA psbA–trnH and psbD–trnT and nuclear external transcribed spacer (ETS) sequences revealed genetic distinctiveness between the Wyalkatchem (type) population and the Southern Cross and Lake Lefroy populations. This evidence, when used in conjunction with the morphological differences, provides support for the recognition of the new subspecies described herein as Pityrodia scabra subsp. dendrotricha K.A.Sheph. subsp. nov. This new subspecies is of conservation concern because it is currently known only from a few, isolated populations; the typical subspecies remains Critically Endangered because it comprises one extant population. A description of both subspecies, a key and images are provided.


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