Narcissus, the daffodil genus, exhibits an unusual diversity of sexual systems, with populations that are monomorphic, dimorphic or trimorphic for style length. Associated with this variation are striking differences among species in floral morphology and pollination biology. This diversity provides an opportunity to investigate the evolution of mating polymorphisms, and to determine how floral...

Floral traits that reduce self-pollination in hermaphroditic plants have usually been interpreted as mechanisms that limit the genetic consequences of self-fertilization. However, the avoidance of sexual conflict between female and male function (self-interference) may also represent an important selection pressure for the evolution of floral traits, particularly in self-incompatible species. H...

In tristylous populations, mating-type frequencies are governed by negative frequency-dependent selection typically resulting in equal morph ratios at equilibrium. However, Narcissus triandrus generally exhibits long-styled (L)-biased populations with a deficiency of the mid-styled (M)-morph. Here we used a pollen-transfer model and measurements of female fertility in natural populations to inv...

It is becoming increasingly important that support is provided for users who are dealing with complex information spaces. The need is driven by the growing number of domains where there is a requirement for users to understand, navigate and manipulate large sets of computer based data; by the increasing size and complexity of this information and by the pressures to use this information efficie...

Three studies tested the hypotheses that the activation of communal mental representations promotes relationship commitment (communal activation hypothesis) and that this effect is stronger among narcissists than among nonnarcissists (Communal Activation x Narcissism hypothesis). Across experimental, longitudinal, and interaction-based research methods, and in participant samples ranging from c...

Compounds that promoted the growth of pollen tubes were isolated from the style of Rhedodendeon muerenatum and were identified as azalein, (+)-catechin, and (-)epicatechin. Among these compounds, 50-100ppm of (+)-catechin or (-)-epicatechin increased the growth of pollen tubes in thmetlia japoniea, R. mueronatum, Slyrax japoniea, and Pinus densij7bra by 16-20%. These compounds had no significan...

Flower senescence is a highly controlled developmental event that culminates in the death of the floral organs. Most research on flower senescence has focused on the perianth, since it typically determines the commercial life of the flower. The mechanism by which the perianth dies differs between species: in some flowers, wilting is the primary symptom of senescence whereas in others, the peria...