Scouler's Heliotrope: Valerian scouleri
A. Corn-salads or Plectritis: The Genus Plectritis - Annuals with simple stems or branches arising singly from the axils. Flowers clustered in head-like or interrupted spike-like inflorescences. All leaves simple with entire margins.
B. Heliotropes and Valerians: The Genus Valeriana - Perennials. At least some leaves (usuall on stem) pinnately compound or pinnatifid.
C. Blue-flowered Corn-salad: Valerianella locusta - Annual with dichotomously branched, weak stems. Flowers in cymose clusters in a flat-topped inflorescence. All leaves simple with entire margins. Flowers pink or blue in small heads or cymes with subtending, linear bracts. Corollas small, up to 2 mm long.