A new species of Misopates Raf. (Scrophulariaceae, Antirrhineae)

Misopates pontiense sp. nov. is described from one population located in the north-west of the Iberian Peninsula. It is an annual, living on charred soils. Its distinguishing characteristics include its seeds, which have a carinate dorsal face and an encircling rounded ridge with cylindrical papillae, but lack a median ridge on the ventral face. Morphological characters and taxonomic affinities are discussed.     

Isolation and characterization of microsatellite loci in the highland papaya Vasconcellea × heilbornii V. Badillo (Caricaceae)

Nine polymorphic microsatellite loci were identified in the tropical plant Vasconcellea ×heilbornii and used to estimate allelic diversity in two populations of southern Ecuador. Allelic richness ranged from two to five alleles, observed heterozygosity ranged from 0.150 to 0.947 and expected heterozygosity ranged from 0.186 to 0.701. Most of these markers also amplified microsatellite loci in two other Vasconcellea species (Vasconcellea stipulata and Vasconcellea cundinamarcensis). Hence, these markers will be useful for population genetic analysis and the evaluation of genetic diversity and gene flow in these species.     

Spatial and environmental determinants of vascular plant species richness distribution in the Iberian Peninsula and Balearic Islands

Using an exhaustive data compilation, Iberian vascular plant species richness in 50 times 50 UTM grid cells was regressed against 24 explanatory variables (spatial, geographical, topographical, geological, climatic, land use and environmental diversity variables) using Generalized Linear Models and partial regression analysis in order to ascertain the relative contribution of primary, heterogeneous and spatially structured variables. The species richness variation accounted for by these variables is reasonably high (65% of total deviance). Little less than half of this variation is accounted for spatially structured variables. A purely spatial component of variation is hardly significant. The most significant variables are those related to altitude, and particularly maximum altitude, whose cubic response reflects the occurrence of the maximum number of species at the highest altitudes. This result highlighted the importance of Iberian mountains as hotspots of diversity and the relevance of large and small scale historical factors in contemporary plant distribution patterns. Climatic or energy-related variables contributed little, whereas geological (calcareous and acid rocks) and, to a lesser extent, environmental heterogeneity variables (land use diversity and altitude range) seem to be more important.     

SENSORY EVALUATION BASED ON VERBAL JUDGMENTS

Studies of the repeatability and the homogeneity of expert panel scores in sensory profiling show that lasting and reliable evaluations of food products are difficult to obtain: strong inter- and intra-individual differences are commonly observed. Our hypothesis is that this variability is due to quantification methods that consist of asking panelists to furnish quantitative values (by attributing a numerical point to perceived intensity) and that using natural language in the form of verbal judgements in a hierarchical tree would allow improving the reliability of sensory evaluations. This hypothesis was tested by comparing a numerical value scale and a specific hierarchical semantic scale that subjects devised themselves prior to the experiment. The products (chocolate dessert creams) were evaluated using each of the two methods. The results show that the capacity to discriminate between products is better when verbal judgements are used. We discuss the advantages of hierarchical semantic scales for sensory profiling.     

Allozymic variation and divergence in three species of Antirrhinum L. (Scrophulariaceae-Antirrhineae)

An allozymic study of three wild species of Antirrhinum L. A. lopesiamum Rothm., A. mollissimum Roihni. and A. microphyllum Rothm. is described. All are members of subsection Kickiella Rothm., and are narrow-range endemics of the Iberian Peninsula. The variability of the different loci, as well as the number and mobility of the alleles, differ among the three species, a demonstration of the usefulness of allozymes for the systematics of the genus. The finding of alleles unique to each species indicates high divergence among species suggesting ancient diversification, and supports the hypothesis of a geographical model of speciation. All three species show high levels of within-species variability, mainly partitioned within populations, while between populations genetic differentiation is low. Correlations between population size, sample size and genetic variability, and the usefulness of allozymic data for conservation purposes, are discussed.     

Population dynamics of three songbird species in a nestbox population in Central Europe show effects of density,climate and competitive interactions

Unravelling the contributions of density‐dependent and density‐independent factors in determining species population dynamics is a challenge, especially if the two factors interact. One approach is to apply stochastic population models to long‐term data, yet few studies have included interactions between density‐dependent and density‐independent factors, or explored more than one type of stochastic population model. However, both are important because model choice critically affects inference on population dynamics and stability. Here, we used a multiple models approach and applied log‐linear and non‐linear stochastic population models to time series (spanning 29 years) on the population growth rates of Blue Tits Cyanistes caeruleus, Great Tits Parus major and Pied Flycatchers Ficedula hypoleuca breeding in two nestbox populations in southern Germany. We focused on the roles of climate conditions and intra‐ and interspecific competition in determining population growth rates. Density dependence was evident in all populations. For Blue Tits in one population and for Great Tits in both populations, addition of a density‐independent factor improved model fit. At one location, Blue Tit population growth rate increased following warmer winters, whereas Great Tit population growth rates decreased following warmer springs. Importantly, Great Tit population growth rate also decreased following years of high Blue Tit abundance, but not vice versa. This finding is consistent with asymmetric interspecific competition and implies that competition could carry over to influence population dynamics. At the other location, Great Tit population growth rate decreased following years of high Pied Flycatcher abundance but only when Great Tit population numbers were low, illustrating that the roles of density‐dependent and density‐independent factors are not necessarily mutually exclusive. The dynamics of this Great Tit population, in contrast to the other populations, were unstable and chaotic, raising the question of whether interactions between density‐dependent and density‐independent factors play a role in determining the (in) stability of the dynamics of species populations.     

Decoupling of reproduction and growth: an unusual pattern in the life cycle of the Mediterranean geophyte Narcissus serotinus

The unpredictable seasonality of the Mediterranean climate imposes on the development of specific life‐cycle phenologies such as those seen in geophyte species that have a period of dormancy to avoid stressful abiotic conditions. To date, two life‐cycle strategies are recognized in Mediterranean geophytes. In some species, growth and reproduction occur in different seasons (hysteranthous geophytes), whereas in others these two processes occur at the same time (synanthous geophytes). A study of the life cycle of the autumnal‐flowering Narcissus serotinus in three populations over two consecutive years confirmed that neither the hysteranthy nor the synanthy strategy could be applied to this geophyte. Rather, reproduction and growth occur simultaneously, but in different plants. A strong correlation was found between bulb weight and the presence of reproductive or vegetative plants.     

An Introduction to Thomas Hunt Morgan and Lilian Vaughan Morgan

Welcoming remarks are given. Various phases in the lives ofThomas Hunt and Lilian V. Morgan are presented.     

The effects of dazomet, fenaminosulf, and soil ridges on red core disease of strawberry

Fenaminosulf applied as a single soil drench soon after planting and growing plants on ridges 305 mm high decreased the incidence and severity of red core (Phytophthora fragariae). Pre-plant treatment with dazomet and growing plants on raised rows 100 mm high were ineffective. The % number of diseased roots was the most useful estimate of disease in evaluating the efficacy of treatments and the interaction of disease and yield. The relationship between disease and yield was highly significant, negative and apparently linear. Disease accounted for a higher proportion of the variation in yield in the first fruiting year than in the second. There was a close correlation between plant size in June and yield in July.     

DNA Polymerase Potentials of Sea Urchin Embryos

THE possible involvement of RNA-instructed DNA polymerase in differentiation has been proposed by Temin¹. Here we present evidence that partially purified polymerase fractions prepared from 16-cell sea urchin embryos, which can undergo normal development through gastrulation, are able to support RNA-directed, as well as the expected DNA-directed, DNA synthesis. The results reported lead us to suggest that the observed RNA-instructed DNA synthesis may be mediated by polymerases other than that responsible for DNA-dependent DNA synthesis.