Fitness was estimated for each replicate flask in the common garden assay as population exponential rate of increase. There was added variance in fitness among sites (F33,68 = 2.03, p=0.007) and among fronds within sites (F68,102 = 3.26, p<0.0001) (Table 4). The variance among fronds within sites was roughly twice as large as the variance among sites.
Table 4. Variation in fitness measured in the common garden assay