• The analysis of metal distribution in Imperata cylindrica, a perennial grass isolated from the banks of Tinto River (Iberian Pyritic Belt), an extreme acidic environment with high content in metals, has shown a remarkable accumulation of iron. This property has been used to study iron speciation and its distribution among different tissues and structures of the plant. • Mössbauer (MS) and X-ray diffraction (XRD) were used to determine the iron species, scanning electron microscopy (SEM) to locate iron biominerals among plant tissue structures, and energy-dispersive X-ray microanalysis (EDAX), X-ray fluorescence (TXRF) and inductively coupled plasma emission spectroscopy (ICP-MS) to confirm their elemental composition. • The MS spectral analysis indicated that iron accumulated in this plant mainly as jarosite and ferritin. The presence of jarosite was confirmed by XRD and the distribution of both minerals in structures of different tissues was ascertained by SEM-EDAX analysis. • The convergent results obtained by complementary techniques suggest a complex iron management system in I. cylindrica, probably as a consequence of the environmental conditions of its habitat.

The latest publications on Sarcocornia taxonomy and phylogeny recognize six taxa in this genus on the Iberian Peninsula: S. perennis, S. fruticosa, S. alpini, S. alpini subsp. carinata, S. hispanica, and S. pruinosa. The present study represents a comprehensive revision of the different taxa in the Sarcocornia genus present in Western Mediterranean Europe by means of morphological, micromorphological and phylogenetic internal transcribed spacer (ITS) analysis. Morphological and micromorphological data were studied from Sarcocornia samples from 113 populations in coastal salt marshes and inland salt pans in Portugal, France, Spain and Italy. Sixteen new ITS sequences were obtained from Mediterranean Sarcocornia species and analysed together with previous reported data. Published karyological, ecological and biogeographical data from Western Mediterranean Europe were also reviewed. The results indicate the presence of a new species, S. lagascae, found growing in coastal Mediterranean areas of the Iberian Peninsula. The species S. fruticosa was found to be absent from the Iberian territories.

The Tinto River (Huelva, Spain) constitutes a complex and singular system characterized by extreme acidity and high concentrations of iron and other metals (Cu, Co, Mn, Zn, Pb, As) of its soils and waters. Traditional mining activity and the resulting intensive deforestation have eliminated its natural vegetation. Communities of the endemic Erica andevalensis colonize the fluvial terraces of the mining areas of the Tinto River, from drier to more humid soils, reaching its optimum in the proximity of rivers and streams. Concentrations of 22 (S, K, Ca, Mn, Fe, Co, Ni, Cu, Zn, As, Pb, Sr, Cr, Na, Mg, Al, Sc, Ti, Rb, Cd, Ba, Hg) elements have been determined for soils and E. andevalensis specimens at several points near the origin of the river. Erica andevalensis shows a remarkable capacity to survive with meager quantities of nutrients and an extraordinary tolerance to high concentrations of heavy metals. However, this heath does not show a lack of nutrients (Ca: 2012–5942 ppm; K: 223–3771 ppm; Mg: 883–2566 ppm) nor an excess of metals in its tissues (Fe: 73–514 ppm; Cu: 9–16 ppm; Co: ND–2 ppm). These abilities make E. andevalensis an ideal candidate for revegetation of mining areas and phytostabilization of heavy metal contaminated soils. These characteristics together with the exclusive extreme habitat on which E. andevalensis grows, make it possible to classify it as a metal bioindicator, e.g., for Cu.