Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Silene latifolia occurs as an annual, biennial or short-lived perennial. Common garden and greenhouse experiments were used to examine the nature of this variation in life history among populations from Manitoba and Ontario. In a common garden, a majority of individuals lived for two years, and were reproductive in both. Populations differed in mean length of the pre-reproductive period, number of reproductive seasons, life span, reproductive output, and in sex ratio. Manitoba populations were less likely to reproduce in their first year than were Ontario populations. Elgin County populations were more likely to be iteroparous than were London city populations. Populations were not separable on the basis of habitat. Families within populations differed in several of the life history traits. Male and female flowering patterns differed over years, and among individuals with different life history tactics. Capsule production patterns resembled male flowering patterns more than female flowering patterns. Some population and family differences seen in the common garden were reproduced in a second year. Some of the variation was environmentally sensitive, and did not show the same pattern in both years. Fitness traits in the common garden and in greenhouse experiments were often either positively correlated, or uncorrelated. White cockle females made serial adjustments in reproductive output within a season. This may have prevented the expression of reproductive costs.



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