Campanula exigua
 The annual flower of the bluebell family Campanula exigua has several common names including chaparral bellflower rock harebell and Rattan campanula. It is a rare plant endemic to California and is found in a few isolated spots around Mount Diablo State Park in the east Bay Area. It grows out of rocky and gravel soils sending up several long stems filled with milky sap and bearing sparse tiny leaves. At the end of each stem grows a bell-shaped bright blue-violet flower.