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The taxonomic boundaries of Centaurea L. species and infraspecific taxa are often blurred by hybridizations. However, counterbalancing genetic isolation contributes to maintaining taxonomic limits and fostering rapid speciation processes. Radiant (R) and non-radiant (NR) capitula are two major floral morphs present in Centaurea. However, it is unclear how gene flow affects the distribution of floral morphotypes across populations and taxa. We have investigated the taxonomic differentiation and potential effect of genetic isolation in R and NR populations of Iberian Centaurea sects. Jacea (Mill.) Pers. ex Dumort. and Lepteranthus (Neck. ex DC.) Dumort. A total of 510 individuals from 58 populations (12 taxa) were analyzed using 165 amplified fragment length polymorphism (AFLP) markers. Genetic diversity and structure parameters were estimated at the taxon, population, and floral morphotypic levels. We tested whether there was correlation between population pairwise fixation index (Fst) genetic distances and the inbreeding coefficient (Fis), taken as a surrogate of reproductive isolation between the R and NR morphotypes of each group, and also taking into account geographic distances, using distance-based redundancy analysis (dbRDA). We also performed isolation by distance (IBD) tests between different floral morphotypes, aiming to infer the impact of genetic isolation on evolutionary and taxonomic divergence of the individuals. The taxa of Centaurea sects. Jacea and Lepteranthus constitute independent evolutionary lineages. Most of the detected genetic clusters match the taxonomic circumscription proposed in our most recent treatments. Genetic diversity was highest in C. debeauxii Godr. & Gren. subsp. debeauxii and subsp. grandiflora (Gaudin ex Schübl. & G. Martens) Devesa & Arnelas and in C. jacea L. subsp. angustifolia (DC.) Gremli (R) and lowest in C. nevadensis Boiss. & Reut. (NR) within the Centaurea sect. Jacea clade, whereas it was highest in C. linifolia L. within the Centaurea sect. Lepteranthus clade. Population-level dbRDA tests did not detect a significant correlation of R versus NR genetic distances and Fis values in any of the studied cases; by contrast, they detected significant correlation with longitude (C. jacea subsp. angustifolia, C. debeauxii, C. linifolia–C. stuessyi Arnelas, Devesa & E. López) or latitude (C. nigra L.). IBD analysis at the individual level showed that, in addition to geography, other morphotype-related factors may affect the genetic differentiation of R versus NR morphs in C. nigra, C. debeauxii, and C. linifolia–C. stuessyi. These results suggest that the fixation of the different morphs within the same taxon or group may be explained by geographic isolation, though we could not discount other potential unknown factors that could have contributed to microspeciation in these recently divergent populations, which originated only several thousands of years ago.

Centaurea is one of the richest but less investigated genera of tribe Cardueae (Asteraceae). We reconstructed an updated phylogeny of Iberian species of Centaurea sects. Centaurea, Jacea, Lepteranthus and Phalolepis by sampling representatives from 48 taxa (~60% of the taxonomic variation). Phylogenetic trees and haplotypic networks were based on ITS and trnLF sequences, and Bayesian dating analysis on ITS data. We found two main lineages within this monophyletic group: (1) a W Mediterranean Centaurea and Phalolepis plus C. diffusa (CP) clade; and (2) an E Mediterranean – Eurosiberian Jacea and Lepteranthus (JL) clade. Our analyses provide new reconstructions for species of C. sects. Jacea and Lepteranthus that support new taxonomic circumscriptions. The inferred divergence times indicated succesive splits of the CP and JL lineages during the Miocene (e.g. CP/JL, Serravalian; Jacea/Lepteranthus, Tortonian; C. hyssopifolia, C. gr. janeri, C. gr. exarata, Messinian) and the Pliocene (C. linifolia/C....

Many studies have tried to assess the role of both deterministic and stochastic processes in community assembly, yet a lack of consensus exists on which processes are more prevalent and at which spatial scales they operate. To shed light on this issue, we tested two nonmutually exclusive, scale-dependent hypotheses: (1) that competitive exclusion dominates at small spatial scales; and (2) that environmental filtering does so at larger ones. To accomplish this, we studied the functional patterns of tropical montane forest communities along two altitudinal gradients, in Ecuador and Peru, using floristic and functional data from 60 plots of 0.1 ha. We found no evidence of either functional overdispersion or clustering at small spatial scales, but we did find functional clustering at larger ones. The observed pattern of clustering, consistent with an environmental filtering process, was more evident when maximizing the environmental differences among any pair of plots. To strengthen the link between the observed community functional pattern and the underlying process of environmental filtering, we explored differences in the climatic preferences of the most abundant species found at lower and higher elevations and examined whether their abundances shifted along the elevation gradient. We found (1) that greater community functional differences (observed between lower and upper tropical montane forest assemblies) were mostly the result of strong climatic preferences, maintained across the Neotropics; and (2) that the abundances of such species shifted along the elevational gradient. Our findings support the conclusion that, at large spatial scales, environmental filtering is the overriding mechanism for community assembly, because the pattern of functional clustering was linked to species' similarities in their climatic preferences, which ultimately resulted in shifts in species abundances along the gradient. However, there was no evidence of competitive exclusion at more homogeneous, smaller spatial scales, where plant species effectively compete for resources.

En este estudio se llevó a cabo una sinopsis del género Paspalum L. en la Península de Yucatán, México. Se reconocen 23 especies en el área de estudio, se proporcionan claves de identificación, descripciones morfológicas, mapas de distribución, así como información acerca de su fenología, hábitat y distribución. Se reconocen dos especies endémicas de la Península de Yucatán, P. mayanum y P. sparsum, localizadas en áreas abiertas de la selva baja caducifolia.

ResumenEn este trabajo se presenta el listado florístico, incluyendo las formas de vida de las angiospermas presentes en las sabanas de San Miguel Allende (Campeche) y de Chacho Lugo (Yucatán). Se registraron 142 especies pertenecientes a 96 géneros y 36 familias, siendo las plantas herbáceas las que tienen la forma de vida dominante. El valor Ij obtenido fue de 0.169, lo que demuestra las notables diferencias en la composición florística de cada una de las sabanas, las cuales comparten sólo 24 de las 142 especies registradas. Las características geomorfológicas de cada lugar indican variaciones en la dinámica hidrológica, lo que se refleja en notables variaciones en la composición florística. Así, San Miguel Allende se clasifica como una sabana estacional, caracterizada por la presencia de géneros como Trachypogon y por la escasa presencia de representantes de la familia Cyperaceae; mientras que Chacho Lugo se clasifica como una sabana hiperestacional, donde abundan especies típicas de ambientes más húmedos (Cyperaceae, Eriocaulaceae y Lentibulariaceae). La presencia de endemismos como Echeandia campechiana, E. petenensis y Hampea trilobata, así como la baja presencia de plantas introducidas, muestran la importancia florística y ecológica de estos enclaves tan pobremente estudiados y afectados por las actividades antropogénicas.AbstractIn this paper we present the floristic checklist, including life forms of angiosperms from the savannas of San Miguel Allende (Campeche) and Chacho Lugo (Yucatán). We recorded 142 species belonging to 96 genera and 36 families, herbaceous plants being the dominant life form. The Jaccard index value obtained was 0.169, which shows the significant differences in the floristic composition of each savanna, which share only 24 out of the 142 species recorded. The geomorphological characteristics of each site indicate variations in hydrological dynamics, as reflected in significant variations in the floristic composition. San Miguel Allende is classified as a seasonal savanna, characterized by the presence of genus as Trachypogon and the limited presence of taxa of Cyperaceae, while Chacho Lugo is classified as a savanna hiper seasonal, where species from humid environments are abundant (Cyperaceae, Eriocaulaceae and Lentibulariaceae). The presence of endemic as Echeandia campechiana, E. petenensis and Hampea trilobata and the limited presence of introduced plants show the floristic and ecological importance of these sites so poorly studied and highly affected by human activities.

Two new Andean species belonging to the tribe Senecioneae (Compositae) are described herein, i.e., Dendrophorbium azoguesense from Ecuador and D. varicosum from Bolivia. The species Pentacalia todziae is recorded for the first time in Ecuador and the names Dendrophorbium onae and D. onae var. leonis synonymized to D. scytophyllum. Taxonomic discussions and diagnostic characters to differentiate each species are provided, as well as a distribution map and pictures of living plants when available.

Español. Se ha efectuado la revisión taxonómica de Centaurea sect. Lepteranthus (Neck.) Dumort. en la Península Ibérica. Se reconocen 12 táxones y se hace una nueva combinación: C. gallaecica (Laínz) Arnelas & Devesa, proponiéndose la inclusión de esta especie en la sect. Jacea (Mill.) Pers. Se aporta una clave para la dentificación de los táxones, así como su descripción morfológica e información sobre la distribución geográfica, apetencias ecológicas, fenología y número cromosómico.English. A taxonomic review of Centaurea sect. Lepteranthus (Neck.) Dumort. in the Iberian Peninsula was done. Twelve taxa are recognized and a new combination is proposed, C. gallaecica (Laínz) Arnelas & Devesa, a taxon which is included in a different section, Jacea (Mill.) Pers. A key for the identification of taxa is made, also their morphological description, information on geographical distribution, their ecology, their phenology and their chromosome numbers are given.

Español. Se ha efectuado la revisión taxonómica de Centaurea sect. Jacea (Mill.) Pers. en la Península Ibérica. Se reconocen 12 táxones y se hace una nueva combinación: C. nigra subsp. endressii (Dostál) Arnelas & Devesa. Se aporta una clave para la dentificación de los táxones e híbridos, así como su descripción morfológica e información sobre la distribución geográfica, apetencias ecológicas, fenología y número cromosómico.English. A taxonomic review of Centaurea sect. Jacea (Mill.) Pers. in the Iberian Peninsula was done. Twelve taxa are recognized and a new combination is proposed: C. nigra subsp. endressii (Dostál) Arnelas & Devesa. A key for the identification of taxa and hybrids are provided, also their morphological description, information on geographical distribution, their ecology, their phenology and their chromosome numbers are given.

The morphological variability of Centaurea langei Nyman (Centaurea sect. Centaurea), an endemic to the north-central and north-west Iberian Peninsula, was studied. Seven subspecies with reasonably well-defined areas are recognized, of which C. langei subsp. dominguezii E. Lopez, Devesa & Arnelas is described as new, and for the others the following combinations are proposed: C. langei subsp. exilis (Arenes) E. Lopez, Devesa & Arnelas, C. langei subsp. coutinhoi (Franco) E. Lopez, Devesa & Arnelas, C. langei subsp. geresensis (Arenes) E. Lopez, Devesa & Arnelas, C. langei subsp. kheilii (Pau) E. Lopez, Devesa & Arnelas, and C. langei subsp. rothmalerana (Arenes) E. Lopez, Devesa & Arnelas. Nomenclatural and taxonomic synonyms are provided for each taxon, most of which are typified. For C. langei subsp. dominguezii, the chromosome number was also studied (2n = 18).

Oritrophium yacuriense is described as a new species from the Andes of southern Ecuador. Morphological characters are used in order to distinguish it from the closest species O. repens, which differs mainly in the leaf morphology. The new species occurs in wet herbaceous páramos of the lagoon complex of the Yacuri National Park.

A new species Neomillspaughia hondurensis (Polygonaceae) from Honduras is described and illustrated. This species is morphologically and ecollogicaly different from the other two currently known Neomillspaughia species, being more related to N. emarginata than to N. paniculata . A comprehensive comparison and a key for the three species are provided. Se describe e ilustra la nueva especie Neomillspaughia hondurensis (Polygonaceae) de Honduras. Esta especie es morfologicamente y ecologicamente diferente de las dos unicas especies de Neomillspaughia , estando mas relacionada con N. emarginata que con N. paniculata . Se proporciona informacion comparativa de la nueva especie con las especies relacionadas y una clave para la identificacion de las mismas.

Coccoloba tunii is here described as a new species from Mexico. Morphological characters of the leaf, inflorescence, and fruit show discontinuities among populations of C. tunii and its relative, C. liebmannii. In addition, both species exhibit different geographical patterns, C. tunii is exclusive of the Central Depression and Plateau of Chiapas (Mexico) at mid elevations, while C. liebmannii ranges from Oaxaca to Colima on lowlands along the Pacific watershed.

El género Carduus L. (Cardueae, Asteraceae), tal y como se considera hoy día, comprende unas 90 especies eurasiáticas (Susanna & García-Jacas, 2007), con especial representación en la Región Mediterránea (Kazmi, 1964). Su conocimiento en la Península Ibérica se fundamenta, sobre todo, en las revisiones taxonómicas de Willkomm (1865 & 1893), Kazmi (1963), Franco (1975) y Devesa & Talavera (1981 a & c), y en la información cariológica (Fernandes & Queirós, 1971; Devesa & Talavera, 1981 b; Rosselló et al., 2005), palinológica (Tormo & Ubera, 1988) y sobre diversos aspectos reproductivos de algunos de sus táxones (Devesa & Talavera, 1981 c). Sobre la base de esta información, el género se consideraba representado en la flora peninsular por 19 especies, siendo 26 el número de táxones reconocidos (Devesa & Talavera, 1981 c) sin contar los híbridos, frecuentes también en el territorio. No obstante, al revisar el género –J. A. Devesa– para la obra Flora Iberica (coord. S. Castroviejo), se han encontrando novedades de interés, entre las que cabe destacar la presencia en la flora española de C. acicularis Bertol., cuyas características y afinidades con especies próximas se comentan a continuación. El estudio morfológico y biométrico en el que se fundamenta este trabajo ha sido llevado a cabo en material recolectado por los autores y en el conservado en diferentes herbarios (BC, BCF, COA, COFC, COI, COI-WILLK., JACA, K, LISU, LTR, MA, MAF, MGC, SEV, UNEX).

Coccoloba floresii is here described as a new species from Mexico. Morphological characters of the leaf, inflorescence, and fruit show discontinuities among populations of C. floresii and its relatives, C. barbadensis and C. cozumelensis. In addition, C. floresii is exclusive of the tropical dry forests of Central Depression and Plateau of Chiapas (Mexico) at high elevations. © 2015 Magnolia Press.

Pennisetum setaceum (Forssk.) Chiov. (Poaceae), new locality for the Iberian PeninsulaPalabras clave. Pennisetum, Poaceae, corología, Córdoba, Andalucía Occidental, Península Ibérica.Key words. Pennisetum, Poaceae, chorology, Cordoba, Western Andalusia, Iberian Peninsula.

Centaurea stuessyi is described as new to science from the eastern Iberian Peninsula, Spain. The range of this new species coincides with the zone of overlap of the ranges of two related species, C. antennata (subsp. antennata ) and C. linifolia . The chromosome number found in the new species (2 n = 44) reinforces its differences from C. linifolia (2 n = 22) and C. antennata (2 n = 22). The new species is compared with related species, and a description is given of its ecological preferences.