The Matilija Poppy (Romneya coulteri) is native to California, with a range from Mexico through northern California. This is a drought tolerant species that can be somewhat invasive once established—but, lordy, does one love being invaded by the Matilija with its big, translucent white flower petals, and yellow stamen cores that have been likened to a hard-boiled egg yolk.
Two other fun Matilija facts: the sap of the Matilija is highly poisonous, and the flower (genus Romneya) was named in the Linaean taxonomic system for Irish astronomer John Thomas Romney Robinson (1792-1882). There’s clearly an interesting tangent here, because Robinson was a good friend of Charles Babbage, and there is some evidence that a conversation between the two of them may have helped to spark the idea for Babbage’s Difference Engine (a forerunner of the modern computer).
Tangents aside, I love to create images on my light box that overlay the translucent Matilija with more colorful flowers, as you can see from the sequence below, and also in Matilija Poppies and Mallows and Matilija Poppies and Friends (among many others).