Doug's Mountain Journal
A Chronicle of Natural History on San Bruno Mountain

Doug Allshouse has been writing his seasonal Mountain Journal for many years. We are very pleased to share his reflections on the natural history of the Mountain. Together with David Nelson, he wrote San Bruno Mountain: A Guide to the Flora and Fauna. The book was published by Heyday Books in November 2022 and can be purchased here.

Autumn 2022

After 33 days of fog in July and August, September lightened up a bit with some mild days and sunshine. Autumn 2022 arrived at the tail-end of a 3-day storm that dropped a half-inch of rain and reminded us that it actually does rain here. Then October arrives and decides to mimic summer all over again by setting a record eighteen days of fog for 0.30 inches of precipitation! Ironically, I deliberately scheduled a field trip on the 15th simply because I was afraid of fog in September. Mother Nature plays a cruel joke once again, bats last, and makes a fool out of me. It’s a good thing that humble pie doesn’t taste too bad.

Walking home on the Bog Trail west of Colma Creek I spotted this fuzzy beauty on a low twig. It is known as a spotted tussock moth or mottled tiger moth (Lophocampa maculata) on one of its larval host plants, the Arroyo willow. The larva feeds on various species of poplar and willow across Canada and the western United States. The larvae go through five instars—the period between molts—from July to September. It is in the final instar that larvae are black on both ends and yellow in the middle, so this plump little guy or gal is close to pupating. We also have the western tussock (Orgyia vestusta) that feed on our manzanitas and huckleberries.

September begins the Fall migration when our overwintering birds begin to arrive. While spending some time on Sunrise Point I saw my first Golden-crowned Sparrows and I was thrilled to see about six Western Meadowlarks rustle out of a coyote bush. This species has been nearly absent from the Mountain during winter in recent years. I recall seeing multiple flocks in years past all over the Saddle. Whenever I am on this Point I stand a great chance to see or hear a coyote and this day was no exception. I heard one yipping west of me in the scrub. Our resident White-tailed Kites are usually around and I spotted the male on a coyote bush near the kite. About the time I thought the kite should be flying to his favorite perch, he accommodated my thought by actually flying to the top of his cypress tree which sits just off Sunrise Trail. The trail bends around the east side of this tree.

On a foggy October morning I walked through Fog Forest as the sun was rising. Cool peachy colors were prevalent and soothing. When I got to the picnic meadow I decided to walk up the Sunrise Trail and take in the view. I ran into many female coyote bushes covered in fuzzy glory waiting for a good strong breeze to blow away all those seeds. (Just what we need—more coyote brush)

Along the way I ran across an impressive spider web strung across the trail with foggy dew drops clinging to the silk. On the Point there was a wall of fog to the west and sunshine to the east. This situation sets up a rare and fascinating phenomenon that I call a fogbow. It is actually a rainbow effect with a lot of fog behind it. Imagine a wall of white fog and because the sunlight is shining on it, a brighter white bow forms. The first and only other times I ever saw this was prior to 1995 before the eucalyptus forest was logged along what was the Eucalyptus Loop trail. Walking east from the auxiliary parking lot on the other side of Guadalupe Canyon Parkway meant being bathed in cool gray fog. When the trail poked out of the forest, the sun would greet you with warmth and bright light. If you walked twenty yards east and turned around you would see a white arching fogbow. It is amazing how different that trail is these days, minus those trees. It is now part of the Dairy Ravine Trail.

This is a story that began over a year ago. My co-author’ David, Nelson has set up his iNaturalist app to inform him of any observations made on San Bruno Mountain. One particular species set off alarms and sent us on a treasure hunt and led to the involvement of a couple of botanical scholars to help solve a dilemma. An initial observation of a polypody fern was listed as Polypodium glycyrrhiza, licorice fern. This caused a bit of consternation since the only two polypody species listed in the 1990 Flora of the San Bruno Mountains were P. californicum, California polypody and P.scouileri, leather fern. Most of our leather fern grows up in the boughs of eucalyptus and Monterey cypress trees and California polypody is what was taught to me by my mentor, Jake Sigg, and was also listed in the old flora. Subsequent observations of San Bruno Mountain polypody on iNaturalist were called P. calirhiza.

Looking in eJepson, I copied and pasted all three descriptions into a document. It was like reading a description of identical triplets!! Supposedly a deciding factor was to bite and taste the rhizome; however they all apparently taste like licorice. It was time to call in an expert and Alan R. Smith came to the rescue except, as fate usually works in cases like this, Alan was going to be out of town in January 2022, in the field, doing research for a few months. I also must note that Alan informed us that the only way to actually identify these three species was by chromosome count. Oh, great!

We had our marching orders: obtain glacial acetic acid/alcohol (a very fancy form of vinegar) and collect specimens of fern fronds containing spores that were white; not light green or light brown or dark brown. Several trips were made to various parts of the Mountain before we hit that specific window (late January) when the spores were the right color. We made a special trip to Brisbane Acres because I recalled a rocky wall where the polypody fronds were morphologically different than those we found on open rocky outcrops. We sent our pickled specimens to John Game at UC Berkeley Jepson Herbarium. John did the scientific fact-checking for our book and he held the specimens until Alan returned.

On September 26, 2022 we got word from Alan that he obtained the specimens from John and it appears that all the specimens that we collected were P. calirhiza. Needless to say, the manuscript went to the printer in Illinois in July and the identification is not in our book. It is time to say “adios” to California polypody on the Mountain and welcome the new kid in town, licorice fern; who, it turns out, was always here.

The winter solstice is approaching and the door to my favorite time of year is opening soon. A good bit of rain is welcome and hopefully will drop in and stay for a while. I love it when the Mountain bursts forth with green growth and offers new opportunities to get out and enjoy its wonders.

See you on the Mountain…