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In the early twentieth century, Wilhelm Johannsen's breeding experiments on pure lines of beans provided empirical support for his groundbreaking distinction between phenotype and genotype, the foundation stone of classical genetics. In contrast with the controversial history of the genotype concept, the notion of phenotype has remained essentially unrevised since then. The application of the Johannsenian concept of phenotype to modularly built, nonunitary plants, however, needs reexamination. In the first part of this article it is shown that Johannsen's appealing solution for dealing with the multiplicity of nonidentical organs produced by plant individuals (representing individual plant phenotypes by arithmetic means), which has persisted to this day, reflected his intellectual commitment to nineteenth-century typological thinking. Revisitation of Johannsen's results using current statistical tools upholds his major conclusion about the nature of heredity but at the same time falsifies two important ancillary conclusions of his experiments—namely, the alleged homogeneity of pure lines (genotypes) regarding seed weight variability and the lack of transgenerational effects of within-line (within-genotype) seed weight variation. The canonical notion of individual plant phenotypes as arithmetic means should therefore be superseded by a concept of phenotype as a dual property, consisting of central tendency and variability components of organ trait distribution. Phenotype duality offers a unifying framework applicable to all nonunitary organisms. [ABSTRACT FROM AUTHOR]

Determinants of ecological pattern must include historical effects and sorting processes aside from phylogenetic constraints and adaptive processes. Historical effects partake in site specific historical informations relative to the dynamics of species assemblages and enduring properties of studied species. Species sorting processes define varied proportional representations in assemblages of the same species with different characteristics. These factors were used in determining the covariation among life-history traits of a woody flora in southwestern Spain.

Premise of research. Determination of species boundaries is essential for understanding and preserving biological diversity, yet it remains a difficult task for many plant lineages. Population genetics approaches explicitly taking into account the geographic context of processes driving population divergence and speciation may help to identify species boundaries in complex groups. Here, we adopt this approach to investigate genetic boundaries in an endemic group of trumpet daffodils (Narcissus, section Pseudonarcissi) whose taxonomic distinctiveness remains controversial. Methodology. We analyzed amplified fragment length polymorphism markers from a total of 36 populations (526 individuals) spanning the group's entire distribution range in the southern Iberian Peninsula. To identify the most likely number of distinct genetic groups, model- and nonmodel-based methods (Bayesian, principal coordinates, and neighbor-joining classification) were applied. Effects of long-term historical divergence were dissected from more recent or local differentiation processes using simple and partial Mantel tests. Pivotal results. A major genetic split, consistently supported by the three analytical methods used, differentiated all populations generally ascribed to Narcissus bujei in traditional taxonomic treatments from the rest, which included all populations generally designated as Narcissus longispathus and Narcissus nevadensis. The two groups exhibited contrasting levels of within-population genetic diversity and rarity. Comparative analyses of the relationship between genetic differentiation and geographic distance in these two main genetic lineages suggested that they have remained isolated through a long time period. Separate analyses of genetic and geographic patterns within each major lineage suggested contrasting evolutionary histories. Conclusions. Genetically, geographically, and ecologically well-defined lineages of the Pseudonarcissi section occur throughout the southern mountains of the Iberian Peninsula, generally supporting the traditional taxonomical delimitation of this lineage and qualifying as separate units of conservation. Our findings emphasize the usefulness of molecular data and population genetics approaches in a geographic context to delineate morphologically cryptic species in complex lineages. [ABSTRACT FROM AUTHOR]