Table 2.

Standardized directional selection differentials (S) and gradients (β) on traits measured in a field population (SJM) of Mimulus guttatus in Lassen National Forest, Butte County, California, USA

Trait	n	S (s.e.)	β (s.e.)
Flower size	49	0·91 (0·31)***	0·98 (0·42)**
Anther–stigma separation	50	−0·15 (0·35)	0·17 (0·36)
Julian date of first flower (JDFF)	59	−0·84 (0·27)**	−0·02 (0·01)*
%	18	1·40 (0·61)**	–
δ13C	17	−0·58 (0·73)	–
Biomass	64	0·60 (0·26)†	0·10 (0·37)

Fitness was estimated as lifetime seed production. Gradients were not estimated for %N and δ¹³C due to small sample sizes.

^†P < 0·1 *P < 0·05; **P < 0·01; ***P < 0·001.