Flowering plants aren’t diverse in the intertidal, particularly not on the exposed outer coast. On Oregon shores we are mostly talking about surf-grass, Phyllospadix. Eelgrass, Zostera, washes up on the beaches all the time, especially near estuaries. There are other flowering plants worthy of mention on this page, the ones that pioneer onto the backshore, like dunegrass, Leymus mollis. Where there is no dune system, the willows, Salix, and a few others sometimes get their feet wet.
The plants on this page are from the intertidal zone of exposed northern Oregon coast. I more or less follow the organization and common names in Kozloff (1993) Polar and McKinnon (1994) and Lamb and Hanby (2005), or some combination of those. I also refer to the USDA PLANTS Database. I try to propose ID’s that are correct, but inevitably, there will be mistakes. If you find one I hope you’ll let me know.
Eelgrass, Zostera marina – Eelgrass is at home in the bays and estuaries. It’s appearance on the surf-swept beaches is strictly in the drift line. Eelgrass was featured in Eelgrass in the Wrack and Beach Hoppers Rejoice Over Drift Macrophytes.
Surfgrass, Phyllospadix – I think the one shown below is P. scouleri. It is at home on rocks, exposed by the lowest tides, and like eelgrass, it is sometimes prevalent in the drift line. Surfgrass was featured in Finding yourself in the Infralittoral Fringe and Comparative Photos Show Rocky Intertidal Changes Between 2013 and 2016.
Dunegrass, Leymus mollis – Used to be the dominant grass on the dunes, but now it’s hard to find in the near-monoculture of Ammophila we find on the dunes. Wide grayish leaves set Elymus apart from Ammophila, which has narrow yellowish-green leaves. Leymus mollis is featured in Dunegrass Finds Breathing Room on the Backshore
European beachgrass, Ammophila arenaria – Look for near-monocultures of Ammophila on almost any dune trail.
Dock, Rumex – I’m not sure what species this is, maybe willow dock, Rumex salicifolius. Rumex will pioneer down onto the backshore, but they have broad habitat preferences.
Sea rocket, Cakile edentula – By summer, look for flowering sea rocket wherever there is a well developed backshore.
Beach strawberry, Fragaria chiloensis
A pioneering dandelion –
Willow, Salix – I think this one is Hooker’s willow, S. hookeriana, also known as coastal or dune willow. Wherever the forest drops right down to the beach, especially where there are seeps, Salix can push down toward the intertidal as far as any forest plant – so low that they expose themselves to damage by winter’s high surf. Salix was featured in Sign of the Season.
Kozloff, E. N. 1993. Seashore Life of the Northern Pacific Coast. 3rd ed. University of Washington Press.
Lamb, A. and B. P. Hanby. 2005. Marine Life of the Pacific Northwest. Harbour Publishing.
Pojar , J. and A. MacKinnon. 194. Plants of the Pacific Northwest Coast. Lone Pine Publishing.