Patches of small blue flowers are blooming between the rows of winter beets and chard on a friend’s farm. This is winter speedwell, or Veronica persica. The local speedwells are easy to identify: look for little flowers with four petals, one noticeably smaller than the others. The other distinctive feature is a protruding pair of antenna-like stamens.
Winter speedwell has flowers that rise from the stem on long stalks (aka pedicels), so they stick out beyond the roundish, scallop-edged leaves. Some speedwells are native, but this one is not–though neither is it particularly invasive. 
Flowers Of Marin 