CSIRO PUBLISHING www.publish.csiro.au/journals/asb Australian Systematic Botany 20, 428–447 Resolution of the taxonomy of Eriocaulon (Eriocaulaceae) taxa endemic to Australian mound springs, using morphometrics and AFLP markers Richard J.-P. Davies A , Andrew I. Craigie A , Duncan A. Mackay A,D , Molly A. Whalen A , Judy P.-E. Cheong B and Gregory J. Leach C A School of Biological Sciences, Flinders University of South Australia, GPO Box 2100, Adelaide, SA 5001, Australia. B Gene Discovery and Function, South Australian Research and Development Institute, GPO Box 397, Adelaide, SA 5001, Australia. C Northern Territory Department of Natural Resources, Environment and the Arts, PO Box 30, Palmerston, NT 0831, Australia. D Corresponding author. Email: duncan.mackay@flinders.edu.au Abstract. The Eriocaulon carsonii F.Muell. species complex consists of rare perennial mat-forming forbs endemic to mound springs of central and north-eastern Australia. Even though the complex occurs across a range of more than 1500 km, the springs on which it occurs are naturally rare and highly disjunct, with groupings of springs (‘super-groups’) 200–500km apart. The present paper investigated the taxonomy of the complex by analysing morphometric characters and amplified fragment length polymorphism (AFLP) genetic markers. Morphological measurements were made of 126 samples collected from 23 spring-subpopulations representing 15 spring-groups spread across all nine super-groups on which the complex occurs. Ordination and univariate analysis of data relating to 30 morphological characters revealed five morphologically distinct groups. These groupings were supported by an analysis of 613 AFLP loci markers derived from a subset of samples from all of the same springs. Ordination analysis of the genetic data matrix revealed that the morphological groups were also genetically distinct. It is proposed that the complex consists of five distinct taxa. Two new subspecies (E. carsonii F.Muell. subsp. euloense R.J.Davies and E. carsonii F.Muell. subsp. orientale R.J.Davies) are described, along with two new species (E. aloefolium R.J.Davies and E. giganticum R.J.Davies). All taxa are nationally endangered or critically endangered according to IUCN criteria, except for E. carsonii subsp. orientale which is vulnerable. Introduction The genus Eriocaulon L. (Eriocaulaceae) contains ∼400 species worldwide, most of which are confined to tropical and subtropical regions (Woodland 1997; Judd et al. 1999). Centres of diversity for the genus are South America, Africa and the Indian subcontinent, with Australia having only ∼35 species (Leach 2000). Species in the genus consist mostly of small perennial herbs and are confined to wet habitats or shallow water (Woodland 1997). The genus belongs to the subfamily Eriocauloideae, which is characterised by having twice as many stamens as petals, and nectar glands on the apices of petals (Judd et al. 1999). In Eriocaulon, these nectaries (and others in the centre of male flowers) produce fluid that attracts insects, suggesting insect pollination (Judd et al. 1999; Davies 2005). The taxonomy of Eriocaulon in Australia was, until recently, poorly studied, the only Australia-wide treatment being from the nineteenth century (Bentham 1878). Recent research (Leach 2000) has described nine new species endemic to northern Australia. However, this study did not resolve the taxonomy of the E. carsonii complex (E. carsonii sens. lat.). Eriocaulon carsonii sens. lat. (salt pipewort) is a perennial mat-forming forb which, along with its mound-spring habitat, is listed as nationally endangered under the Australian Federal Environment Protection and Biodiversity Conservation Act 1999. The species is chiefly endemic to Great Artesian Basin (GAB) mound springs, although it also occurs on several springs fed by a similar but localised aquifer adjacent to the north-eastern edge of the GAB (Fensham and Fairfax 2003). Even though E. carsonii has a widespread latitudinal and longitudinal distribution of more than 1500 km (from the base of Cape York Peninsula in northern Queensland to near Lake Eyre in north-eastern South Australia; Fig. 1), super-groups (groups of spring-groups) supporting the species are highly scattered, with some populations up to 500 km from the nearest conspecific populations (Fatchen and Fatchen 1993; Chambers et al. 2003; Fensham and Price 2004; D. Niejalke, Western Mining Corporation, unpubl. data). Significant morphological variation had been noted previously among populations occurring in different spring complexes (G. J. Leach, pers. obs.), probably owing to this © CSIRO 8 November 2007 10.1071/SB07019 1030-1887/07/050428