Age-Specific Survivorship and Reproduction in Phlox drummondii

THE ORGANIZATION OF GENETIC VARIABILITY IN PHLOX DRUMMONDII

“…and Ward (1972). The seed pool of P. drummondii probably is not very long lived (greater than five years) and probably is skewed markedly toward the youngest age classes (Leverich and Levin, 1978). Thus the contribution of an age structured seed pool to a heterozygote deficiency ostensibly is small.…”

“…mcallisteri in open fields on shallow sandy soils of granitic origin on the Edwards Plateau. Reproductive barriers to gene exchange are weak (Erbe and Turner, 1962;Levin, 1976), and the integrity of the subspecies seems due to their ecogeographical isolation. All of the subspecies exhibit gametophytic self-incompatibility, and have the same chromosome number, n = 7.…”

Population Dynamics of Ludwigia Leptocarpa (Onagraceae) and Some Factors Affecting Size Hierarchies in a Natural Population

“…In a sagebrush community, Gottlieb (1977) found that 75% of the plants of the annual species Stephanomeria exigua were smaller than the population mean. Likewise, Leverich & Levin (1979) observed extreme differences in size and fecundity of individuals of the winter annual Phlox drummondii. Juvenile size was correlated with adult reproductive output.…”

“…In Phlox drummondii (Leverich & Levin 1979), more than half of the annual seed crop was produced by only 10% of the flowering individuals (2% of the original cohort). Plant size is often highly correlated with fecundity (Harper & White 1974;Wener 1975;Solbrig 1981) and is frequently a more important factor in determining seed production than is age (Harper & White 1974;Naylor 1976).…”

The realism of models in plant demography

“…Leverich & Levin 1979;Law 1981). Other demographers believe that the sizes of individual plants are more important than age in determining life-history characteristics (e.g.…”