Muir's "sea mosses"

At the turn of the year, I visited the John Muir National Historic Site in Martinez, California. This was my second visit in under a year (I wrote about Muir's life and my previous visit here). My time wandering about his house was more intentional on this recent trip and I took a closer look at the house and the historical items on display inside.

It wasn't long before I discovered an intriguing item in a display downstairs: seaweeds! Muir was a botanist of course – godfather of the giant sequoia, wildflower enthusiast, and a collector of plants on his thousand mile walk to Florida – but I had no idea that he had collected marine algae!

A few specimens of Microcladia coulteri on display at the Muir National Historic Site in Martinez, California.

Muir's "sea mosses" were collected in Pacific Grove on the Monterey Peninsula in central California, a location that has long been popular with seaweed enthusiasts. For example, some of the 100+ year old specimens of marine algae that I've had a chance to observe in the University herbarium at Berkeley over the years were collected at Pacific Grove.

Microcladia coulteri (center) on Chondracanthus
exasperatus (right) at Carmel Point, Monterey Co., CA,
June 2014.

The plants on display appear to be Microcladia coulteri, a common species in central and northern California. M. coulteri typically grows as an epiphyte on other red seaweeds such as Mazzaella and Chondracanthus. It is a fantastic species for the artist since it dries easily, adheres to herbarium paper readily, and has such a beautiful branching pattern.

Muir’s seaweeds were pressed on small pieces of paper and assembled into a book as a gift for his sister. A few loose plants are on display next to the booklet (it is uncertain if they were pulled out of the booklet). The loose plants are still in good shape. Seaweed specimens can last hundreds of years if they are mounted on acid-free paper and preserved carefully. I’m not sure how Muir obtained the specimens – if they were washed ashore or even given to him by another naturalist – but it is fun to think of him in suit and hat, knee deep in chilly water at low tide, marveling at the botanical and zoological treasures of the intertidal universe.