Work-study student Katherine is the author of today’s entry. She writes:
Morchella esculenta sensu lato, or in the broad sense, is distributed globally. However, the “species” is taxonomically confusing, as explained by Michael Kuo: “The short version of the story is: the name has been confusing since it was created; it has been applied uncritically for centuries; and, here in North America, we have at least four genetically distinct candidates for the name (which represents a European mushroom that can’t be compared to our mushrooms until someone figures all of this out)” (Michael has also posted a longer version). The species was originally described from collections made in Eurasia, and since this photograph is from The Netherlands, it may indeed be the true species as originally published. Then again, perhaps not; in “Species diversity within the Morchella esculenta group (Ascomycota: Morchellaceae) in Germany and France”, a 2004 paper by Kellner et al. (doi:10.1016/j.ode.2004.07.001), differences in the internal transcribed spacer (ITS) region within the nuclear ribosomal DNA (nrDNA) of 22 different samples of Morchella esculenta s.l., suggested the presence of three distinct species.
The Royal Botanic Gardens, Kew has a species profile for Morchella esculenta that makes mention of the taxonomic difficulties of the group, as well as a detailed description of the fruiting bodies and spore deposits.
Species of this genus in general are collectively referred to as the morels or sponge mushrooms. The name of the genus is derived from the old German word Morchell, a term meaning edible fungus or morel, and the species name from the Latin esculentus meaning edible, or good to eat. Unsurprisingly, Morchella esculenta, or the common morel, is considered one of the best edible fungi, and highly sought after by mushroom hunters. Fruiting bodies of Morchella esculenta are noted by the Royal Botanic Gardens, Kew as being “quite nutritious, containing high-quality protein, and being rich in minerals and low in calories”. However, all sources I’ve read also note that they must be cooked prior to consumption! Uncooked morels are known to cause digestive upsets. Morels showing signs of decay should also be avoided, as they can be poisonous. David Arora in his book Mushrooms Demystified notes that one should always “split them length-wise to check for millipedes, slugs, and other critters that like to hide inside”. Despite these issues, morels “[are] so esteemed in Europe that people used to set fire to their own forests in hopes of eliciting a bountiful morel crop the next spring!” Morels may also be preserved by being canned, frozen, or dried.
The Wikipedia entry on Morchella esculenta claims that this fungus species has also been used in Chinese traditional medicines for the treatment of “indigestion, excessive phlegm, and shortness of breath”. Recent laboratory studies (in rodents) have shown “anti-tumour effects, immunoregulatory properties, fatigue resistance, and antiviral effects” and “antioxidant properties”.