Common Name: Morel, Sponge Mushroom, Molly moocher and Merkel (Southern Appalachians), Dryland fish – The common name morel is of obscure Germanic provenance, probably a simplified version of the generic name from the same etymology.
Scientific Name: Morchella spp – Theories as to the derivation of Morchella include an old German name for mushroom and the genus of the mulberry tree Morus due to the resemblance of the morel to the mulberry fruit.
Potpourri: Morels are surely the most celebrated of edible fungi in North America. They were among the first fungi to be classified as belonging to a genetic group owing to their unique taxonomy; a sponge on a stalk. The Greek word for sponge from which fungus derives may well be due to similarities between morels and sea sponges; morels may well be the first fungi named by humans. The type species morel, M. esculenta (edible in Latin) or yellow morel, is normally indicated in guide books as having been identified by Carolinus Linnaeus in the 18th century, the Swedish originator of the taxonomic system still in use today. The black morel M. elata (exalted in Latin) was first identified by Elias Fries, also Swedish, one of the first mycological taxonomists. Morels are arguably the most recognizable fungus in the world, excepting only perhaps the iconic Amanita muscaria which, with its blood red cap accentuated with snowflake white flecks, is the choice for everything from animation to tchotchkes. Many European languages share similar names for the English morel such as the French morille and the German morchel; they are called morels in Poland, Turkey, Hungary and Italy. However, depending on how you define it, the morel is not really a mushroom.
While the terms mushroom and fungus are considered synonymous according to pragmatics, they are semantically different; a mushroom is one type of fungus. The kingdom fungi has two major divisions (sometimes subphyla or phyla): Ascomycota, the so-called cup fungi, and Basidiomycota, which includes puffballs, stinkhorns, brackets and a number of other obscure physiologies in addition to the ubiquitous mushrooms. According to Kendrick’s The Fifth Kingdom a mushroom is “a fleshy basidioma, usually stalked and with a cap (pileus) beneath which gills or fleshy tubes are covered with or lined with the hymenium.” The hymenium is the spore bearing surface wherein the major dichotomy of the fungi resides; basidiomycetes have basidia, the club shaped bodies in which (usually four) spores are produced and ascomycetes have asci, sac-like structures in which (usually eight) spores reside. As language is evolutionary, mushroom is trending as a more ecumenical term that can be applied to designate the fruiting body of any fungus. The important point is that morels are ascomycetes.
Ascomycetes originated in the Paleozoic Era from a common ancestor and are therefore monophyletic, somewhat surprising in consideration of their morphological divergence and extensive speciation. It is estimated about three quarters of all identified fungi are ascomycetes, about 70,000 species. Most are asexual, reproducing with spores genetically identical to the source generally comprising the yeasts, molds, and rusts. The sexual ascomycetes form macroscopic fruiting bodies typically have a distinctive cup shape by which they are commonly known in addition to some unusual outliers like the hypogeal truffles (Tuber spp) and the anthropomorphic dead man’s fingers (Xylaria polymorpha). In morels, the spore-bearing cup surface hymenium has been compartmentalized into the characteristic honeycombed pits and carried aloft on a hollow stalk, presumably by the evolutionary advantage of increased spore dispersal. Based on modern genetic evaluation of mutation rates, morels are monophyletic with a single ancestor of North American provenance that first appeared in the Cretaceous Period about 125 million years ago; they have since morphed into many different species whose taxonomy is only now being tentatively established. The verisimilitude of morels comes as something of a surprise; their distinctive and recognizable crenelated cone morphology belies a disparate genetic diversity.
The taxonomy on Morchella is complex, a fact that is only recently becoming manifest with the advent of DNA based associations. This is not all that unexpected, as the morels have one of the more variegated reproductive systems, unusual even in the rarefied nuances of fungal sexuality. Morels are multinucleate to the extreme; each morel cell can have as many as fifty different haploid nuclei. Haploid refers to the number of chromosomes in a cell or ‘n’ – fungi spend most of their lives as haploid organisms. Most other life forms, humans included, are diploid or ‘2n’. Fungi become diploid for reproductive purposes whereas humans create the haploid sperm and egg to create the diploid zygote. When the fruiting body of the morel mycelium is forming, only two of the fifty-odd haploids will serve as the genetic agents for the parent organism in the ascospore. As there are hundreds of possible combinations, it is likely that each of the eight ascospores in the ascus is genetically distinct. According to Beug and the Bessettes in Ascomycete Fungi of North America, “Practically, this means that in a cluster of 4 to 20 morels, each morel in the cluster is likely to be genetically distinct.” Real basidiomycete mushrooms have only two nuclei per cell (so you see, morels really aren’t mushrooms). While the work of understanding the true nature of morel relationships (morelity?) is on-going, it seems that North America has a black or M. elata clade of about 14 species and a yellow or M. esculenta clade of about 5 species; in eastern North America, as of now there are three blacks and three yellows. For all of the genetic differentiation, so far as is now known, all morels are equally edible and, in the lexicon of mycophagists, choice.
To say that a fungus is edible is usually only half of the story. Many people who rarely if ever eat wild foods will develop nausea which may devolve to the more pronounced physical rejection of the offending substance altogether. Nausea is an evolutionary adaptation to protect animals from eating something unknown and therefore possibly harmful. In addition to their inherent alien chemistry (fungi are mostly chitin), many fungi also have noxious volatile compounds which must be evaporated by heating; it is therefore a matter of policy among all credible mushroom organizations that edible fungi must all be thoroughly cooked. Morels are among the many edible fungi that are toxic (at least to some) if eaten raw. Fortunately, cooking imparts an epicurean flavor that aficionados describe as reminiscent of hazelnuts to a host of gourmet dishes; reports of adverse morel reactions are therefore rare. Morels, like many edible fungi are also quite nutritious; they contain more protein than most vegetables, are rich in vitamins E, D, K and the B group, and their fiber is conducive to proper intestinal function.
Having established that morels are delectable and nutritious if cooked, it is necessary to establish how, when and where you find them. Finding morels is quite challenging, as the habitat that is likely to favor their growth is imprecise and inconsistent and the fungi are mercurial in the extreme. How to find morels is to be persistent and diligent. Pattern recognition skills are important as morels share the color palette with fallen leaf litter, betraying their presence only by trompe d’oeil stalk-borne wavy fissures. When to find morels is a matter of temperature and elevation or latitude. The most widely accepted soil temperature range for the morel mycelium to fruit is between 50 and 55 °F. Since it is not practical to go out with a thermometer and randomly probe soil temperatures, the rule of thumb is at least one full week with a minimum nocturnal temperature of 50 °F. According to this measure the morel season starts in the south and moves northward from April to May with some adjustments necessary for the cooler temperatures at higher elevations (2.5 °F drop every 1,000 feet). Another method for ‘when’ is to employ phenology, to use the temperature cues of other plants as surrogate thermometers. Among the many indicators, a favorite is ‘when an oak leaf is the size of a squirrel’s ear’ (which they resemble), as this seems to best capture the wisdom of the merkel-hunting mountain people. Others include when the redbuds and dogwoods bloom or when violets first appear.
The ‘where’ is a matter of perennial debate and will likely never be settled. Finding morels is more serendipity and secrecy than science with its own lore of Elysian Fields replete with morchelloid bounty. According to myriad self-proclaimed experts, morels may be found under tulip poplars, white and green ash, hickory, elm, striped maple, sycamore, oaks, in abandoned apple orchards, and, most significantly, in burned areas after a fire. In some parts of Europe, laws were passed to prevent the burning of forests that had previously been set to promote morel growth the following year. David Aurora in Mushrooms Demystified captures the frustration of many in noting that “Morels usually grow outdoors: in forests (under both hardwoods and conifers) and open ground – under hedges, on road cuts and driveways, near melting snow, in gravel – In other words morels grow wherever they please – but only when conditions are favorable.” The only correct answer to where to find morels is to know where the hypogeal morel mycelium grows, which can only be established by finding morels, a fungal catch-22. There is a good reason for morel inconstancy. Morel mycelia form sclerotia, masses of large cells several inches in diameter described as resembling a slippery walnut. The sclerotium is a nutrient reservoir, allowing the fungus to survive adverse conditions for decades. The upshot is that the morel mycelium can choose whether to form a primordium cum fruiting body or whether to await more favorable conditions. Coaxing the sclerotium to fruit is fundamental to commercial cultivation. In 1982, Ronald Ower succeeded in demonstrating a consistent process. U.S. Patent number 4,594,809 was issued in 1986 specifying the series of operations necessary and sufficient for morel cultivation, about two weeks after Ower was murdered in San Francisco.
As with many edible fungi, there is a doppelgänger – the Brain mushroom Gyromitra esculenta which is suggestively known as the false morel. The species name is an unfortunate choice, as edible is true only with extreme caution; it has been consumed with impunity for centuries. False morels produce gyromitrin which contains monomethylhydrazine, a component of rocket fuel. Ingestion of this chemical is inimical to the fundamental physiology of the human body and can result in symptoms ranging from nausea to death. While cooking volatizes some but probably not all of the gyromitrin, it is potentially lethal. Some people who eat fungi are old, and some are bold, but those who seek to be both old and bold are usually eliminated from the gene pool.