Detrended, modelled first leaf dates for 856 sites across North America for the period 1900–2008 are used to examine how the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) separately and together might influence the timing of spring. Although spring (mean March through April) ENSO and PDO signals are apparent in first leaf dates, the signals are not statistically significant (at a 95% confidence...

Summary Phenotypic variation is a fundamental requirement for evolution by natural selection. While evidence of phenotypic variation in natural populations abounds, its genetic basis is rarely understood. Here we report variation in the ability of plant‐colonizing Pseudomonas to utilize histidine, and its derivative, urocanate, as sole sources of carbon and nitrogen. From a population of 164 phyllosphere‐colonizing Pseudomonas...