Its easy to tell if you’re looking at a gum plant. All the different species have big yellow daisy-like flowers perched atop a green nub that is studded with fleshy hooks. Before the young buds bloom they ooze a white sap that looks exactly like fresh Elmer’s glue.
San Francisco gum plant (Grindelia hirsutula var. maritima) only grows near the coast, on hills and bluffs from Marin to Monterey. I spotted these specimens on a recent hike to Chimney Rock on Point Reyes. Distinguish this plant from its cousin, coastal gumplant, because it grows on the hills instead of the salt marshes–but mainly because it doesn’t have perennial woody stems. San Francisco gum plant can vary dramatically in size, from 8 inches to nearly 5 feet. The plants I saw had hairy leaves, but according to the Marin Flora the leaves are usually hairless (aka “glabrous” in botany-speak).
Surprisingly, the Elmer’s glue doesn’t seem to have had any historical uses (that I’ve been able to unearth). But the dried leaves and buds were used to treat bronchial conditions including asthma.
Though there are three different species listed in the Marin Flora, it’s worth noting that some experts think that they all are actually part of the same species, Grindelia hirsutula.