Untangling a species complex of arid zone grasses (Triodia) reveals patterns congruent with co-occurring animals

• We delimit taxa in a species complex of grasses using morphology and molecular markers.
• Geographic partitioning of genetic lineages is congruent with ranges of co-occurring animals.
• Greater lineage diversity and endemism in the Pilbara are consistent with it being a refugium.
• Individuals with ITS copies from different taxa suggest hybridization.