Nature Notebook, September 10, 2020


The autumn equinox arrives Tuesday, Sept. 22 with equal hours of day and night. In the Celtic tradition, it is the second great harvest festival, Mabon, a time to rest after hard labor, give thanks for the abundance of nature, and prepare for the long winter darkness ahead.

My unexpected migration east, prompted by an evacuation order for my road that ended this past Friday, gave me the chance to compare what happens in the warmer inland valley of Petaluma and the cooler coastal climes of West Marin. The name “Petaluma” comes from the Coast Miwok word for hillside ridge or hillside back, and I made my way up and down many of the small hills west of the river. Along the way, buckeye trees were noticeably farther along than those in West Marin. They have already dropped their leaves and the fuzzy green seeds are readily apparent, unlike the buckeye tree in my yard, which is just beginning to drop leaves.   

Here on the coast, the late summer coyote brush is in bloom, with separate male and female, yellow, flowering evergreen shrubs. The low-growing shrub may be first on the scene in burnt or disturbed areas, as its fuzzy seeds are carried by the wind. Firefighters have noted flammable mosses draping trees, most likely two common types of fruticose lichen: “old man’s beard (Usnea sp.) and lace lichen (Ramalina menzies). These can grow several feet along host trees. Lichen also takes a crustose form, lying flat on surfaces, and foliose forms, as small trees or shrubs sprouting off surfaces.