Petasites japonicus subsp. giganteus.
ID on sign
I know this has been ID'd before, but I can't seem to find the name....
Again, next to Pescadero Creek
Interesting leaf shape along Big Creek near where it meets the sea...
growing in wet area alongside Westside Road beneath steep slope
This budding flower is called Palmate Coltsfoot in my field guide, and Western Sweet Coltsfoot on this site.
The plants commonly referred to as Butterbur are found in the daisy family Asteraceae in the genus Petasites. They are mostly quite robust plants with thick, creeping underground rhizomes and large Rhubarb-like leaves during the growing season. Another common name for many species of this genus is Sweet Coltsfoot.