Giant coryopsis, near The Towers on Santa Cruz. This variety of coreopsis is just like the garden plant, but bigger. It's one of those things that is much bigger or smaller out there: tiny foxes, pygmy mammoths, and so on. Like most of the native island plants, it appears mostly in crevices or steep slopes shunned by more recent invaders.
Alas, in the first edition of this post I wrote "Giant Corynactis". Corynactis are under the water, not on land; and I've never seen one larger than a centimeter across.