Dried Mushrooms—What’s the Deal?

© Else Vellinga, Ph.D.
Lab
Original publication: Mycena News, December 2012

The last few years Tom Bruns et al. have been organizing many forays and collecting trips to Point Reyes National Seashore, Yosemite National Park, and the Mendocino area. The purpose of these trips is partly to teach students about the different species that can be found in these areas, partly to inventory these parks and regions. And the way we carried out the inventory part was not just by making a list of all the species we saw, but by collecting mushrooms, photographing them, making notes, drying them in a food dryer, and then preparing those collections for permanent storage in the university’s herbarium, which is a dry and cool resting place for dried specimens. More often than not, a dried up mushroom loses its shape, its colors, and its smells when submitted to the dryer, but its microscopic characters stay intact, and its DNA as well (if the collections are properly cared for).


A herbarium cabinet at UC Berkeley, showing folders with packages and trays with boxed collections. Photo by the author.

The reasons for keeping the specimens are clear: we can get back to the specimens, look at them under the microscope, get the DNA out and compare it with that of other species and specimens. Did we get the name right in the first place? Perhaps not, but we can update the identification. Specimens can be, and in fact are, used to describe new species.

If we didn’t have these specimens but had only a list of species that had been collected, we might keep guessing about the reality of the names we had been using. We might be talking about totally different species with our co-mycologists at the other side of the country, without realizing it. The Europeans who arrived in North America called a bird with a red breast ‘robin’: they used a European name for the American species now called Turdus migratorius, whereas the European robin, Erithacus rubecula, is equally red-breasted but quite different, and yet, they now both go under the name ‘robin’. The same is happening in mycology: names given to species occurring in Europe are used for California species. Sometimes this is correct (e.g., for the hedgehog, Hydnum repandum), but in most cases it is not. For instance, the local purple laccaria which we called Laccaria amethystina was renamed Laccaria amethysteo-occidentalis, as it is quite different from the European species. But if we do not have material at hand to check, we will never find this out. Hence, a herbarium comes in handy.

The second reason to keep material is to get a historic record. Thanks to herbarium specimens, the presence of the death cap (Amanita phalloides) in California could be traced back to 1938, when it was collected in the grounds of the Del Monte Hotel in Monterey; older specimens under that name turned out to be different species. Other examples of the value of specimens come from Europe, where changes in distribution, fruiting time, and occurrence frequency have widely been noted. Meticulous record keeping and herbarium collections give an ongoing account of the state of the mushroom world. For instance, in the Netherlands, the hawkswing mushroom, Sarcodon imbricatus, has drastically declined, and where it was once widespread it is now only known from a handful of sites (see here); nitrification, acidification and changes in forest management are the culprits for this dramatic decline. Herbarium records in Norway were used to predict changes in the distribution patterns of species, and research on changes in fruiting period and time relied heavily on records and specimens that were collected over a long period of time in the U.K., Switzerland and Norway.

The two local university herbaria are part of a nation-wide effort to make all the herbarium records of the macrofungi (all fungi with visible fruitbodies) available on line. The Harry D. Thiers herbarium at San Francisco State University has an estimated 60,000 collections, with a heavy focus on California mushrooms collected by the late Harry Thiers, his students, and his successor Dennis Desjardin and his students. The University herbarium at UC Berkeley has a collection of around 50,000 fungal specimens that go back to the late 1800s with many early collections from Point Reyes, Mount Tamalpais, and Cooke’s collections from the Shasta area. By exchange, gifts and purchases, other parts of the U.S.A. are represented as well.

The full name of the project is “The Macrofungi Collections Consortium, Unlocking a biodiversity resource for understanding biotic interactions, nutrient cycling and human affairs”, spearheaded by Barbara Thiers and Roy Halling of the New York Botanical Garden, and funded by the National Science Foundation. It is a 3-year project and the goal is to get the label data for all macrofungal collections of around 35 herbaria on line. The first 400,000 records and several thousand photographic images and images of field notes, are already available at the Mycological Collections Portal web site, curated by Scott Bates. The labels of the collections will be photographed. These photos will generate database records, including the name of the specimen, when, where and by whom each specimen was collected. Creating records from images will be not so much of a problem for the typed labels, but the many handwritten scribbles might be more difficult to interpret. For around 10% of the collections, the dried mushrooms themselves will be photographed. Even though shape, sizes and colors of gilled mushrooms change after drying, there is still important information left and polypores and puffballs do not change much at all during their stay in the aridity of the herbarium.

Notebooks, field record books and notes on cards with macroscopical descriptions will also be digitized. Again these are, for the most part, hand-written.

The task of decyphering mycologists’ handwriting where technology fails will be in the eyes and hands of volunteers—those of you who love reading mushroom facts and descriptions and are good at seeing the words through the up-and-down strokes of fountain pens—let us know! Harry Thiers’ notes will be included, and his hand writing is notoriously difficult to interpret.

Students, both undergraduate and graduate, will work on the project participating in all kinds of capacities. They put bar code labels on the boxes and folders holding the specimens, photograph the material, type the main info (species name, collector’s name) into the database, and get to know their herbarium and its contributors. The ultimate goal is to get them enthusiastic about living fungi. Summer interns at NYBG wrote fascinating posts on mycologists and fungi (links to these pages are in the left bar of here).

The MyCoPortal web site is the serious brother to Mushroom Observer; at both sites maps can be produced, but at the former, these are based on identified and vouchered material. At the latter, they are based on observations with identifications that can range from a long night spent with books and microscopes to a quick look at the photo by someone in another part of the world. Right now, both sites show that big swaths of the U.S.A. are under-researched, and that the more difficult fungal groups definitely need our attention too.

The last four months I have spent quite some time at the UC herbarium; updating names, sticking barcodes on, and giving the collections some well-needed love and care. I came across material that has been in the hands of famous mycologists, such as Setchell (after whom Setchelliogaster was named) and Murrill. I saw many old collections from Point Reyes and Mount Tamalpais and I would love to know whether these species are still around in our area. This brings me to the present day again, where I started this writing: modern collections are as valuable as the old ones; they hold the key for our knowledge and understandings in the future!

Some background reading

Important web sites

Else Vellinga, Ph.D., is interested in mushroom taxonomy and has been studying mushrooms in California and beyond for years. A frequent contributor to Mycena News, she is also fascinated by interactions between fungi and other organisms. In her free time she knits, and knits, and knits!