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. It appears in the quarterly newsletters of the Yerba Buena Chapter of the California Native Plant Society (CNPS). We are very pleased to share his reflections on the natural history of the Mountain. Together with David Nelson, he is writing San Bruno Mountain: A Guide to the Flora and Fauna. The book will be published by Heyday Books in 2022.

After a juicy rainy season produced a spectacular spring and a hopeful summer, autumn was a dud. A bizarre heat spell in usually cold foggy August virtually killed the poison oak, pink everlasting and gumplant fireworks just as they were getting started. Oh sure, the fog came back in September, and along with a brief rainstorm, it managed to dump almost 4/10 of an inch of precipitation. In fact, July-September set a record for precipitation of 1.01 inches of fog, annihilating the same 3-month period in 2017 of 0.81 inches. All things considered, autumn was a busy time to be out and about.

The lower bridge on Colma Creek was mostly rebuilt but not without some casualties. During the 2016-2017 rain season that produced over 36 inches a seep was created on the trail just 10 feet southwest of the bridge. Eventually some ambitious visitor laid down two pieces of wood over the seep to keep shoes somewhat dry. It never was much of a wet spot, but as the bridge and rails were being replaced some enterprising ranger engineered a foot-deep trench and mini-bridge over the seep. The creation of the trench wiped out 8-10 low clubrush plants, Isolepis cernua, despite flag markers nearby. Fortunately, I have a clubrush growing in a large pot on my deck and it has produced some offspring that will be planted there when they grow up.

The rains of 2016-2017 also produced a large sinkhole under the Old Guadalupe Trail where there was a pipe that carried Colma Creek under the road. Leaks from the old pipes eroded the soil under the road and caused the asphalt to fall into the hole eating up about 60% of the road. For two years there was a large steel plate covering the sinkhole and work began in September and finished in mid-October. It’s a bit higher tech than the old one, but it’s not guaranteed to last any longer. One morning I decided to take a shortcut from the Bog Trail to the Old Guadalupe Trail through the cypress and eucalyptus that led to some leather fern (Polypodium scouleri) discoveries. Leather fern is an epiphyte that generally is seen growing in boughs of trees in the forest. My discovery was large communities of these ferns growing on the ground. Epiphytes get their nutrients through their leaves and have rudimentary root systems that are designed to be toeholds to anchor them to their tree hosts. It’s unusual to see these large communities on soil but they certainly seemed happy.

On October 10, an 11-acre grassfire burned down from the Ridge Trail in Brisbane Acres next to Army Road. This is one my favorite meadows in spring when the mule ears, Wyethia angustifolia, are blooming in their vivid yellow glory. Fire recharges the soil with minerals and nutrients, laying the groundwork for a dazzling spring wildflower show. I have yet to hike out and look at the meadow, but I can’t wait to see it next spring. Hopefully some fire poppies will pop up along with those beautiful mule ears.

One of our most valuable autumn plants is horseweed (Erigeron canadensis) which is in the sunflower family, Asteraceae. This erect, highly branched but rather narrow plant is generally 0.5-1.5 m tall and roughly resembles an inverted horse’s tail. The leaves are linear, erect, and occupy the entire stem. The inflorescence is heavily branched with ascending clusters of urn-shaped flowers. The flower does not fully open when mature, and then forms a pappus, so it seems to never be in flower. It seems to be either closed and not yet in bloom, or alternatively fuzzy and past its prime. The flower is white to light yellow to green. While horseweed sounds like a terrible moniker, it’s quite a valuable food plant for small seed-eating birds in fall and early winter. Native to North and Central America, it is now found world-wide. Native Americans found many uses for horseweed. Inserting crushed flowers into the nostrils induces sneezing, a tea made from leaves was used to treat dysentery, a tea boiled from the root cured menstrual issues, and it could be used as a diuretic that made one sweat. The former genus Conyza comes from Greek konops, meaning flea and the name fleabane comes from using the leaves in a pet or human bed to rid it of fleas. Young seedlings and leaves can be boiled and eaten, and dried leaves can be used as seasoning like tarragon. An essential oil made from the leaves can be used to flavor soda, candy and condiments. My guess is that you will not look at horseweed in the same way as you did. I think it is an immensely beautiful and elegant piece of botany.

My Fall field trip is usually a walk in Dairy and Cable Ravines, two adjacent NNW-facing ravines above and east of Radio Road. This year’s version took on enlightenment when one of my attendees was Cynthia Powell, Executive Director of Cal Flora, a Berkeley-based non-profit whose website I practically live on for plant identification and distribution. It is a godsend, rich with information and has expanded its benefits with a smartphone application called Calflora Observer Pro. Photograph a plant and it records a location with your name on it for a database. I downloaded it the evening before and I am still learning about all the features, but Cynthia took about 30 photos and assembled a log of those plants. If you haven’t visited Calflora.org, do it.

A couple of things stood out for their “out-of-season” blooming. Wight’s paintbrush, Castilleja wightii, typically a late spring-summer bloomer, was shooting up new stalks of whitish-yellow bracts in October. It is a facultative or hemi-parasite that has green leaves for photosynthesis but steals water and minerals through its haustoria, finger-like appendages that tap into its host’s roots. On Kamchatka Point there are two endemic manzanitas: San Bruno Mountain manzanita and miniature manzanita. Miniature manzanita, Arctostaphylos uva-ursi forma suborbiculata, is a distinct form of bearberry manzanita or Kinnikinnick that has very small, spoon-shaped leaves that are concave instead of convex. Manzanitas shouldn’t be flowering this time of the year, but we did spot a few berries which is quite unusual at this time of the year. And on the way back down we spotted a purple owl’s clover, Castilleja exserta ssp. latifolia, blooming way out of season, but what a delight to see!!

And that wasn’t the end of the surprises! We spied a huge mound nest of Red Mound Ants, Formica integroides, right on the trail’s edge, home to ferocious collectors of carbon detritus and food. You might say—it was quite a day, all things considered.

See you on the Mountain....