Poppy

Eschscholzia californica or California poppy is a species of flowering plant.

Background
Coming from the family Papaveraceae, it is native to the United States and Mexico, and the official state flower of California. Ambassador Dennis Crocker in the NCR Embassy wears one on his lapel. It can also be seen on the pre-War California state road sign outside of Nipton.

Behind the scenes
The California poppy is based on the real world equivalent of the same name that became the official state flower of California in 1903.