<div><div>En el presente estudio el número de cromosomas de la subsp Mimosa xanthocentra. subsericea var. subsericea, M. balansae, M. chacoensis, M. rojasii todos con 2n = 26 y M. lupinoides con 2n = 52 ha sido reportado en primer término. El 2n = 52 de M. somnians subsp. viscida var. viscida y de M. somnians subsp. somnians var. somnians son nuevas y diferentes de las 2n = 26 publicados antes para M. somnians var. somnians de Argentina. M. debilis con 2n = 26 también difiere de las cifras reportadas previamente para M. debilis var. debilis de Argentina con 2n = 52. El 2n = 26 de adenocarpa M. bimucronata var. coincide con la cifra reportada para M. bimucronata var. bimucronata, y el número de M. polycarpa var. spegazzinii con 2n = 26 se confirma</div></div>

Se confirma la observaci&oacute;n de Ekman sobre la condici&oacute;n de silvestre de GossypiumEkmanianum y se corrige su pa&iacute;s de origen

<div>En este trabajo se presentan los números cromosómicos de 50 accesiones de Malvaceae de</div><div>Argentina, Bolivia, Brasil, Chile, México y Paraguay, las mismas representan 17 géneros y 40</div><div>especies. Para las siguientes 28 especies se presenta el número cromosomico por primera</div><div>vez: Cienfuegosia conciliata 2n=20, Hibiscus striatus 2n=52, H. adscensionis 2n=72,</div><div>Phragmocarpidium Heringeri 2n=50, Malachra radiata 2n=56, Pavonia Friesii 2n=56, P.</div><div>fruticosa 2n=56, P. subrotunda 2n=56, Monteiroa Reitzii 2n=20, Tarasa nototrichoides 2n=10,</div><div>Tropidococcus pinnatipartitus 2n=24, Cristaria disssecta 2n=12, Gaya Bordasii 2n=12,</div><div>Pseudabutilon cinereum 2n=16, Abutilon fluviatile 2n=16, A. laxum 2n=16, Wissadula Fadyenii</div><div>2n=14, Sida vespertina 2n=14, S. Glaziovii2n=28, S. glomerata 2n=14, S. hirsutissima 2n=28,</div><div>S. planicaulis 2n=28, S. Rodrigoi, 2n=28, S. ulmifolia 2n=28, S. Hatschbachii 2n=42, S. Reitzii</div><div>2n=42, S. aggregata 2n=16, S. rufescens 2n=32</div>

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Liolaemus is the most specious genus of the Squamata lizards in South America, presenting exceptional evolutionary radiation and speciation patterns. This recent diversification complicates the formal taxonomic treatment and the phylogenetic analyses of this group, causing relationships among species to remain controversial. Here we used Next-Generation Sequencing to do a comparative analysis of the structure and organization of the complete mitochondrial genomes of three differently related species of Liolaemus and with different reproductive strategies and ploidy levels. The annotated mitochondrial genomes of ca. 17 kb are the first for the Liolaemidae family. Despite the high levels of sequence similarity among the three mitochondrial genomes over most of their lengths, the comparative analyses revealed variations at the stop codons of the protein coding genes and the structure of the tRNAs among species. The presence of a non-canonical dihydrouridine loop is a novelty for the pleurodonts iguanians. But the highest level of variability was observed in two repetitive sequences of the control region, which were responsible for most of the length heterogeneity of the mitochondrial genomes. These tandem repeats may be useful markers to analyze relationships of closely related species of Liolaemus and related genera and to conduct population and phylogenetic studies.

This chapter aims to update the chromosomal features evaluated by classical and molecular cytogenetic techniques. Karyotype variability detected within and among species was very useful to unravel the taxonomy of the genus and to establish relationships among species. This chapter includes analyses of chromosome morphology, heterochromatin, rDNA loci, as well as dispersed and clustered repetitive sequences. A critical review of the genome sizes of Arachis species is also provided. The usefulness of chromosome data is presented in three examples. The first one deals with the origin of the cultivated peanut. Molecular cytogenetics evidenced that the varieties of A. hypogaea may have had a single genetic origin, that A. monticola is a direct tetraploid ancestor of peanut, and that A. duranensis (A genome) and A. ipaënsis (B genome) are the diploid progenitors of the AABB tetraploids. The second one pointed to the analysis of the origin of the rhizomatous tetraploids and their relation to the unique diploid species (A. burkartii) of section Rhizomatosae. The cytogenetic data suggest that A. burkartii has to be discarded as a genome donor of the tetraploids, and that the latter may have had independent origins involving different species. The third one concerns the species of section Arachis, and how the chromosome data aided in the establishment of the genome groups (A, B, D, F, G, and K).