Data from: Ten cases of divergence in the seedling ecology of Dudleya (Crassulaceae)

Dudleya is a genus of succulents consisting of 49 terminal taxa. Many are
restricted to narrow geographic ranges with closely related forms living
in differing climates. Previously, we found an intriguing set of
correlations among nine more or less sympatric Dudleya: species with a
smaller mature body size had a lower tolerance for an arid inland climate
compared to larger bodied species. Thus, we were motivated to test for
rules caused by convergent evolution. We sampled 20 populations from
locations across much of the range of the genus. The 20 populations were
placed into 10 pairs of close relatives. For each pair, one form was
judged to be more mesophilic and the other to be more xerophilic, based on
climate-of-origin. We measured germination rate, survival through the
summer drought in a coastal garden, and survival through the summer in an
inland garden. We hypothesized (among other things) that the xerophilic
taxa would have larger mature body sizes and greater rates of survival
than mesophilic relatives; however, this and other expected patterns were
not repeated across the 10 pairs. Members of pairs have diverged both in
various morphological traits and in seedling ecology, but evolution has
seemingly not converged on rules. For nearly all taxa, habitat dependence
was clear, i.e. plants survived significantly better through the summer at
the coastal garden than at the inland garden. Quite possibly the
correlations we previously found were caused by divergence between
particular lineages coupled with phylogenetic conservatism. Considering
the 10 pairs, Dudleya divergences appear to each evolve
individualistically.