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Background and Aims The dynamics of genome evolution caused by whole genome duplications and other processes are hypothesized to shape the diversification of plants and thus contribute to the astonishing variation in species richness among the main lineages of land plants. Ferns, the second most species-rich lineage of land plants, are highly suitable to test this hypothesis because of several unique features that distinguish fern genomes from those of seed plants. In this study, we tested the hypothesis that genome diversity and disparity shape fern species diversity by recording several parameters related to genome size and chromosome number. Methods We conducted de novo measurement of DNA C-values across the fern phylogeny to reconstruct the phylogenetic history of the genome space occupation in ferns by integrating genomic parameters such as genome size, chromosome number and average DNA amount per chromosome into a time-scaled phylogenetic framework. Using phylogenetic generalized least square methods, we determined correlations between chromosome number and genome size, species diversity and evolutionary rates of their transformation. Key Results The measurements of DNA C-values for 233 species more than doubled the taxon coverage from ~2.2 % in previous studies to 5.3 % of extant diversity. The dataset not only documented substantial differences in the accumulation of genomic diversity and disparity among the major lineages of ferns but also supported the predicted correlation between species diversity and the dynamics of genome evolution. Conclusions Our results demonstrated substantial genome disparity among different groups of ferns and supported the prediction that alterations of reproductive modes alter trends of genome evolution. Finally, we recovered evidence for a close link between the dynamics of genome evolution and species diversity in ferns for the first time.

There are relatively few studies of DNA content in the Vernonieae (Asteraceae) tribe. The first studies were realized in the Lessingianthus genus and determined the DNA content of 25 species. After DNA content, ploidy level and the total karyotype were compared in 6 Chrysolaena species. The aim of this study was to present, for the first time, the DNA content values of Vernonanthura and Vernonia and to thereby expand knowledge of the Vernonieae tribe. A total of 19 natural populations belonging to the genera Vernonanthura and Vernonia were studied for the first time. The results were compared with other Vernonieae genera and with other Asteraceae tribes. Our results found that Vernonieae have the smallest range of 1C value variation in Asteraceae. Furthermore, there were differences in the DNA content of Vernonia and Vernonanthura. These results show that low DNA content and herbaceous habit in Vernonia are characters derived from the higher DNA content and woody habit present in Vernonanthura. These results could indicate a hybrid origin of one species and allow the determination of both the ploidy and chromosome number of other taxa. The results observed in Vernonanthura species showed a highly significant correlation between 1C-value and latitude. Fil: Vega, Alvaro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina Fil: Dematteis, Massimiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina

A new species of Vernonanthura (Asteraceae), V. nana, from the Brazilian state of Paraná is described and illustrated. The new species resembles V. squamulosa but differs in its geographical distribution, habitat, shape and pubescence of the leaves, and involucre length. Fil: Vega, Alvaro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina Fil: Dematteis, Massimiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina

Pollen grains from 16 species of Vernonanthura H. Rob. were studied. All the species exhibit the type 'A' pollen characteristic of the genus. These grains are spheroidal to prolate-spheroidal, subechinolophate, tricolporate, with a continuous tectum which is densely microperforate, exhibiting lophae surrounding irregular depressions and having prominent spines. Despite most of the species having a similar pollen type, some taxa can be recognised by the morphology of the spines. According to the spine index (length/width), the species analysed can be divided into three groups having respectively short, medium and long spines. In addition to the size of the spines, some taxa can be distinguished by spine shape. Vernonanthura pinguis (Griseb.) H. Rob. has spines which are constricted at the base, while V. oligactoides (Less.) H. Rob. exhibits small conical spines. Vernonanthura nudiflora (Less.) H. Rob. and V. schulziana (Cabrera) H. Rob. have spines with rounded apices. This study confirms that Vernonanthura is a well-defined group based on pollen characteristics and that pollen morphology is a significant feature in the characterisation of species and genera of Vernonieae. © 2011 AASP - The Palynological Society. Fil: Vega, Alvaro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina Fil: Dematteis, Massimiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina

Floral microcharacters of the genus Chrysolaena H. Rob. (Vernonieae, Asteraceae) were analysed in detail for the first time in order to evaluate the taxonomic position of conflictive species in the group. The results were also compared with studies carried out in species of related genera. In addition to distinctive microcharacters previously studied in some species of the genus, other characters such as trichome types of the corolla, style, anthers and cypselae have been analysed for the first time. The presence of glandular apical appendage and cypselae are common characteristics among species Chrysolaena. In addition to these, this study shows that presence of glands on the style and corollas is another consistent characteristic in the genus. However, the absence of basal stylar node would not be a diagnostic character since this varies widely among species. The results indicate that most of the microcharacters of Chrysolaena analysed are quite consistent in the genus, but they are no more consistent than the pollen morphology (type ’C’) and chromosome base number (x D 10). Until now, these last two features would be most useful for separating Chrysolaena from the related genera Lessingianthus and Lepidaploa. At species level, the results show that related species can be distinguished by the different combinations of floral microcharacters. The value of microcharacters could be increased if they are combined with other morphological, cytological, and palynological data. Fil: Via Do Pico, Gisela Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botanica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botanica del Nordeste; Argentina Fil: Vega, Alvaro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botanica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botanica del Nordeste; Argentina Fil: Dematteis, Massimiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botanica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botanica del Nordeste; Argentina

Los géneros Lepidaploa (Cass.) Cass. y Lessingianthus H. Rob.(Vernonieae, Asteraceae) fueron establecidos para separar a las especies inicialmente ubicadas en Vernonia Schreb. sect. Lepidaploa (Cass.) DC. subsect. Axilliflorae Benth.& Hook. y Vernonia sect. Lepidaploa subsect. Macrocephalae Benth.& Hook., respectivamente. Tal como se delimitan actualmente, Lepidaploa está compuesto por alrededor de 150 especies ampliamente distribuidas en Sudamérica, mientras que Lessingianthus presenta 120 especies con una gran concentración en el sudeste de Brasil. Se estima que gran cantidad de especies todavía incluidas en Vernonia no han sido estudiadas apropiadamente y en consecuencia su posición y estatus taxonómicos permanecen inciertos. En este trabajo se analizó la morfología de los granos de polen y de algunos microcaracteres florales para aportar datos que permitieron transferir seis taxones de Vernonia al género Lessingianthus y otras dos especies del mismo género a Lepidaploa. The genera Lepidaploa (Cass.) Cass. and Lessingianthus H. Rob. (Vernonieae, Asteraceae) were established to separate taxa initially placed in Vernonia Schreb. sect. Lepidaploa (Cass.) DC. subsect. Axilliflorae Benth. & Hook. and Vernonia sect. Lepidaploa subsect. Macrocephalae Benth. & Hook., respectively. As presently delimited, Lepidaploa is comprised of about 150 species widely distributed in South America, while Lessingianthus presents 120 species having a concentration in southeastern Brazil. It is estimated that a large amount of several species still included in Vernonia have not been examined and consequently their taxonomic position remains uncertain. We analyzed pollen morphology and floral microcharacters of several Vernonia species, which allowed the transfer of six taxa previously placed in this genus to Lessingianthus and other two species of the Vernonia to Lepidaploa. Fil: Angulo, Maria Betiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina Fil: Vega, Alvaro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina Fil: Dematteis, Massimiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina

The size and geographical distribution of the genus Vernonia , tribe Vernonieae, has been greatly reduced as a result of several revisionary studies. All species of Vernonia are now confined to the New World with the vast majority in continental North America. Of the South American species that were not placed in other genera in these treatments, but remained in Vernonia [i.e., V. echioides (Paraguay, Uruguay), V. greggii (Mexico), V. incana (Paraguay, Uruguay), V. perangusta (Brazil), V. rubioides (Brazil)], few have been studied in detail to confirm their generic status. Our work shows that V. perangusta is a member of the genus Vernonanthura and is hereby transferred to that genus. We also studied the widespread and variable taxon known originally as Vernonia polyanthes . This species was transferred to Vernonanthura as V. phosphorica (based on Chrysocoma phosphorica) , but the name Eupatorium polyanthes has priority over Chrysocoma phosphorica and thus a new combination for that taxon is also required in Vernonanthura .