Braiding Sweetgrass

belly-button lint.
I lean in close and find lots of baby thalli, little brown discs about
the size of a pencil eraser, scattered over the rock. This is a
healthy population. These juveniles arose either from broken
fragments of the parent or, because of their perfect symmetry,
more likely from specialized propagules called soredia—a little
package of both fungus and alga designed for joint dispersal, so
they’ll never be without their partners.
Even the tiny thalli are dimpled with navels. How fitting that this
ancient being, one of the first forms of life on the planet, should be
connected to the earth by an umbilicus. The marriage of alga and
fungus, Umbilicaria is the child of earth, life nourished by stone.
And people are nourished by Umbilicaria, as the name rock tripe
suggests. Rock tripe is generally categorized as a starvation food,
but it’s not so bad. My students and I make a pot every summer.
Each thallus may take decades to grow, so our harvest is minimal,
just enough to taste. First we soak the thallus overnight in
freshwater to remove the grit it has accumulated. The soaking
water is poured off to leach away the powerful acids the lichen uses
to eat away at the rock. Then we set it to boil for half an hour. It
yields a lichen broth that is quite palatable and rich enough in
protein to gel like consommé when it is chilled, tasting vaguely of
rock and mushroom. The thallus itself we cut into strips that are like
a chewy pasta, making a quite serviceable lichen noodle soup.
Umbilicaria is often the victim of its own success. Accumulation is
its undoing. Slowly, slowly the lichens build up a thin layer of debris
around them, perhaps their own exfoliations, or dust, or falling
needles—the flotsam of the forest. The dusting of organic matter
holds the moisture that the bare rock could not hold and gradually
an accretion of soil creates a habitat for mosses and ferns.