Seed weight is an important predictor of germination success
It is clear that seed weight is an important factor influencing the
germination of both chasmogamous and cleistogamous seeds in our study.
This is to be expected, as larger seed mass has long been linked to more
energy investment and higher germination rates (Green & Hansen 1969,
Hendrix 1984, but see Kitchen & Monsen 1984), although the tradeoff
between seed size and dispersal ability, seed number, and susceptibility
to predation all mitigate the overall fitness benefits of increased seed
size (Gómez 2004, Gundel et al. 2012). Chasmogamous seeds of D.
californica are heavier than cleistogamous seeds, but it was the
cleistogamous seeds that generally outperformed chasmogamous seeds in
our study. Our hypothesis that nonlocal chasmogamous seeds would
outperform nonlocal cleistogamous seeds was primarily motivated by the
genetic differences between seed types, although we would expect seed
weight differences between seed types to reinforce this prediction. We
were surprised to find the reverse phenomenon to be true across all
three source groups in the HD common garden, with a significant seed
type effect showing that non-local, obligately selfed, smaller
cleistogamous seeds significantly outperformed non-local, potentially
outcrossed, larger chasmogamous seeds.