Wednesday, January 27, 2010

Oddities at Año Nuevo - Part 1, Strange Poison

A male elephant seal snoozing on the beach.
His chest has scratch marks from fighting with other males.

Año Nuevo State Park
on the beautiful San Mateo coast of California is famous for beachside viewing of elephant seals and whale watching. Año Nuevo State Park is also the location of a former Ohlone village where archaeologists, tribal members and ecologists are researching ancient fire and land management practices of native peoples. See the California State Parks website for more info about these popular activities.

I would like to report on something else, two natural oddities that surprised me on a recent visit to Año Nuevo State Park: poison oak mutations and butt-wiggling seagulls.

As you come out of the parking lot, follow the Año Nuevo Point Trail to the right of the shipwreck for sneak peeks into the busy village of dense native shrubs. At Año, these areas have been altered by shipping, dairy farming, brussel sprout fields, cattle grazing and sand mining. Under State Park's guidance and with the mitotic grace of time, much of the property has reverted back to near natural conditions. Peer into the dense tangle of shrubs along the trail and notice busy bugs, small birds, the bent-branch signs of mammals, and reptiles, possibly even the endangered and lovely red-headed and turquoised-striped San Francisco garter snake.

Poison oak is one of the common shrubs of the coastal community, so be careful to snoop without touching. But don't be afraid of poison oak - its knitted branches, shiny leaves and berries provide habitat for many insects and feathered, furred and scaled predators. In the short winter of the California coast, poison oak shrubs lose their leaves. This provides an opportunity to admire their scaffolding.

My adventure began when I noticed strange paddle-like deformities on the tips of some of the poison oak branches. At first I thought a cactus was poking through the thicket. But on closer inspection (leaning without touching and via binocs), I realized these structures were flattened poison oak branches with a row of buds lined up shoulder to shoulder on the splayed top. A co-hiker speculated that this phenomena was 'cresting'. Also known as fasciation, this occurs when plant growth that normally pushes forward from a single bud at the tip of a branch, instead occurs at multiple buds forming a flat, ribbon-like or greatly folded structure. These aberrations are thought to be caused by a genetic disorder, bacteria, viruses or insects. Horticulturalists have used this effect to create bizarre ornamental plants.

A crested euphorbia decorating a local restaurant.

As we hiked towards the sea, cries of "There's one!" floated up from our group whenever we saw more PO shrubs sporting these brown fans. Soon we had a game underway to find the most heavily infested bush and the most bizarrely shaped aberration. Passing us on the way to see the famous fighting seals, the Boy Scouts didn't know what they were missing.

See Part 2 as the odd adventures at Año Nuevo State Park move to the beach.

See also:
  • San Mateo County Natural History Association
  • Field Guide to the Plant Galls of California and Other Western States, Ron Russo.
  • Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide, Steve H. Dreistadt.


  1. Ah. So now we know what's going on with that plant at Country Gourmet. Thanks. And I don't care if it happens to PO - bacteria or mutations can happen all it wants to that vile plant, I say!

  2. We sure get around to the same places. Maybe I should start doing restaurant reviews.


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