Caterpillar Phacelia is a staple of the Merced River Canyon west of Yosemite, joining with Live Forever to accessorize dry, rocky areas where other plants can't be bothered to settle. It's a reliable sight every spring along the Hite Cove trail, generally around the March/April boundary. You're far more likely to encounter it here or elsewhere in the canyon than inside the park itself, as it doesn't grow much above 4,000 feet.
Blooms: March - May
Phacelia cicutaria etymology: Phacelia derives from the Greek word for cluster, a reflection of the flowers' habit of appearing in bunches. Cicutaria is a reference to the Cicuta (Water Hemlock) genus, whose leaves are considered to resemble the leaves of Caterpillar Phacelia. (Cicuta is also the Latin term for hemlock.) 1 2 3
This Photo: Along the Hite Cove trail, late March