The bee icon for "Pollinator-Friendly Plants" indicates those species that are particularly hospitable to providing a wide range of California insects with what they need.
Most plants that are not wind-pollinated are pollinated by insects. Grasses and conifers are wind-pollinated, and most of the rest, the annual and perennial wildflowers and trees and shrubs, are insect-pollinated. The co-evolution of our flora with our insects is one of the most compelling reasons for growing California native plants in your garden and supporting their continued presence in our wildlands. Though many commonly used garden plants can supply nectar to bees, butterflies, and other insects, native plants do it just right - the right timing, the right nutritional content, the right floral structure.
Species with this icon are "super-pollinators," particularly conducive to a wide range of insect life, species that will give you a good start if you want to support pollinators in your garden.