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The Anacardiaceae is an important and worldwide distributed family of ecological and socio-economic relevance. Notwithstanding that, molecular studies in this family are scarce and problematic because of the particularly high concentration of secondary metabolites-i.e. tannins and oleoresins-that are present in almost all tissues of the many members of the group, which complicate the purification and amplification of the DNA. The objective of this work was to improve an available DNA isolation method for Schinopsis spp. and other related Anacardiaceae, as well as the PCR protocols for DNA amplification of the chloroplast trnL-F, rps16 and ndhF and nuclear ITS-ETS fragments. The modifications proposed allowed the extraction of 70-120 µg of non-degraded genomic DNA per gram of dry tissue that resulted useful for PCR amplification. PCR reactions produced the expected fragments that could be directly sequenced. Sequence analyses of amplicons showed similarity with the corresponding Schinopsis accessions available at GenBank. The methodology presented here can be routinely applied for molecular studies of the group aimed to clarify not only aspects on the molecular biology but also the taxonomy and phylogeny of this fascinating group of vascular plants. [ABSTRACT FROM AUTHOR]

Until the beginning of the twentieth century there were extensive subtropical seasonal thorny forests surrounding the Pampas grasslands of Argentina, known as the 'Espinal'. In central Argentina there still exist relicts of the Espinal, belonging to the 'Entrerrianense District'. These forests were never described or analyzed in detail. In 2004 we studied 10 randomly located plots of 50 9 2 m. All individuals and stems of woody species were counted and their diameters at breast height (DBH) were measured; individuals with\1 cm DBH were considered juveniles. We recorded 2,300 woody individuals/ ha corresponding to 12 species. The more constant species are the palm Trithrinax campestris (100%), Celtis tala (90%), Prosopis alba and Celtis pallida (both 50%). The plots are relatively homogeneous, but once classified with cluster analysis two groups are formed according to the relative abundance of C. tala and T. campestris; the latter species is more frequent in more open or fire-disturbed habitats. The results of Canonical Analysis of Principal coordinates are in agreement with the classification. We postulate that the differences between both groups are caused by a differential degree of disturbance (probably caused by fires). Both dominant species show abundant juveniles, and the invasion by exotic woody species is limited. These forest relicts are among the last remnants of the massive expansions of forests in central Argentina. Besides their historical value, an urgent call is made for their preservation, sustainable use and defence from biological invasions. [ABSTRACT FROM AUTHOR]