Seed Number

After adjusting for fruit position, ANCOVA indicates that flowering time affects seed production (p < 0.0001); overall, early flowers in

Figure 5.7. Flowering phenology for the early population (EP) and the late population (LP). Natural observations, 1997. Average frequency of flowers are plotted against Julian date (total number of flowers were transformed to a relative frequency from the maximum number of flowers per plot). Julian date 153 corresponds to June 2.

Figure 5.7. Flowering phenology for the early population (EP) and the late population (LP). Natural observations, 1997. Average frequency of flowers are plotted against Julian date (total number of flowers were transformed to a relative frequency from the maximum number of flowers per plot). Julian date 153 corresponds to June 2.

1997 produced more seeds than mid-season flowers. Site and the interaction time x site were not significant.

Average seed number per flower for the EP decreased through the season (rs = -0.373,p < 0.001). Early flowers (opened June 6-8) produced significantly more seeds than flowers from the peak of flowering (opened June 14-18) (p = 0.0093). Early flowers produced an average of 32.01 seeds in contrast to 23.43 seeds for the mid- season flowers (Fig. 5.8A).

Similar to the EP, in the LP, the average seed number per flower decreased through the season (r = -0.370, p < 0.001). Early flowers (opened June 23-25) produced significantly more seeds than flowers from the peak of flowering (opened June 30-July 4) (p = 0.0001). Early flowers produced an average of 36.22 seeds in contrast to 22.91 seeds for the mid season (Fig. 5.8B).

Seed Weight

After adjusting for fruit position, ANCOVA indicates that flowering time (p < 0.01) and site (p < 0.01) affects significantly average seed weight; overall seeds from early flowers in 1997 weighed more than seeds from mid-season flowers. Seeds from EP weighed more than seeds from LP, but this might be compensation, since plants from

Figures 5.8. Average seed number per fruit versus flowering cohort, two populations. For the early population: Early, flowers that opened between June 6 and 8; Mid, flowers that opened between June 14 and 18. For the late population: Early, flowers that opened between June 23 and 25; Mid, flowers that opened between June 30 and July 4. Error bars represent one standard error. (a) Early population 1997. (b) Late population 1997.

Flowering Cohort Flowering Cohort

Figures 5.8. Average seed number per fruit versus flowering cohort, two populations. For the early population: Early, flowers that opened between June 6 and 8; Mid, flowers that opened between June 14 and 18. For the late population: Early, flowers that opened between June 23 and 25; Mid, flowers that opened between June 30 and July 4. Error bars represent one standard error. (a) Early population 1997. (b) Late population 1997.

LP populations produced on average more seeds than the EP population. The interaction time x site was not significant.

Seeds from early flowers were significantly heavier than those from the peak of flowering for both sites (p < 0.05). In EP the average seed weight for early seeds was 1.065 mg and for the mid-season seeds was 0.904 mg (Fig. 5.9A). In LP the average seed weight for early seeds was 0.908 mg and for the mid-season seeds was 0.741 (Fig. 5.9B).

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