Timothy P Holtsford

We explored the extent to which the soil seed bank differed genetically and spatially in comparison to two actively growing stages in a natural population of Plantago lanceolata. All seed-bank...

Clarkia tembloriensis exhibits a wide range of variation among its natural populations in outcrossing rate and in separation of male and female function in space (anther-stigma separation or herkogamy) and...

Inbreeding depression is commonly observed in natural populations. The deleterious effects of forced inbreeding are often thought to be less pronounced in populations with self-pollinating mating systems than in primarily...

Nicotiana section Alatae exhibits great diversity among species in floral morphology, mating system, and predominant pollinators. As a first step towards estimating nectar's role in floral evolution, we studied nectar...

In natural populations where interfertile species coexist, conspecific and heterospecific pollen can be delivered to the stigmas. Post-pollination mechanisms might determine the seed siring success of different pollen donors within...

The heritability and genetic basis of nectar traits have been rarely studied in the field, where plants are exposed to environmental factors that could mask underlying genetic effects. Heritabilities and...

We analyzed floral volatiles from eight tobacco species (Nicotiana; Solanaceae) including newly discovered Brazilian taxa (Nicotiana mutabilis and "Rastroensis") in section Alatae. Eighty-four compounds were found, including mono- and sesquiterpenoids,...

The role of pollinators in plant speciation and maintenance of species boundaries is dubious because most plant species are visited by several types of pollinators, and most pollinator species visit...