February 22, 2022
While out in the valley I am always astounded at the sheer volume of lichens hanging off a variety of trees. Some of them actually look “cloaked,” blanketed with foliose lichens. In the past I have talked about the fishnet lichen, Ramalina menziesii, also called Lace lichen, which is one of our most common light green hanging lichens. Today I want to focus on another group of closely related lichens that are not as common, called horsehair lichens, from the genus Bryoria. Horsehair lichens are composed of intricately branched filaments that often hang down from conifers, less frequently from hardwoods, and resemble tangled masses of hair from a horse’s mane. They can be bright yellow to dark, almost blackish brown. The two most studied species are Bryoria tortuosa, tortured horsehair lichen, and Bryoria fremontii, edible horsehair lichen. One is poisonous and the other is highly edible. The lichen that I have observed in Little Lake Valley looks more like the edible horsehair lichen but only a lichen expert could say for sure. Even though many can be identified by observable characteristics it comes down to chemistry when trying to identify species of the same genus.
In Little Lake Valley, the Bryoria species seem to be predominantly growing on the Oregon ash trees that are in the northern part of the valley. These areas are where we have the most inundation, and where the standing water lasts the longest into summer. It seems to me that the habitat requirements of this species of lichen must include extended inundation of the base trees. When I began to research the group called horsehair lichens, I quickly realized that there are many species of Bryoria found in North America but not many are found in northern California, especially in lowland areas. Horsehair lichens are an important ecological component of woodlands as they are a winter food source for deer and elk and a nesting material for many species of birds. The detritus from falling lichen is a fertilizer for the trees it resides in. Edible horsehair lichen is an important food and medicine resource to many tribes of Native Americans.
Walking along the many Oregon ash tree lined fences in this valley I am curious why the ash trees have an abundance of hanging lichens and moss. It would make for an interesting graduate thesis.