Morchella

Morchella, thetrue morels, is agenusof ediblesac fungiclosely related to anatomically simplercup fungiin the orderPezizales(divisionAscomycota). These distinctivefungihave ahoneycombappearance due to the network of ridges with pits composing theircaps. Morels are prized bygourmetcooks, particularly inCatalanandFrench cuisine, but can be toxic if consumed raw or undercooked. Due to difficulties incultivation, commercial harvesting of wild morels has become a multimillion-dollar industry in the temperateNorthern Hemisphere, in particularNorth America,Turkey,China, theHimalayas,India, andPakistanwhere these highly prized fungi are found in abundance.
Typified byMorchella esculentain 1794, the genus has been the source of considerabletaxonomicalcontroversy throughout the years, mostly with regard to the number of species involved, with somemycologistsrecognising as few as three species and others over thirty. Currentmolecular phylogeneticssuggest there might be over seventy species ofMorchellaworldwide, most of them exhibiting high continentalendemismand provincialism.
The genus is currently the focus of extensivephylogenetic,biogeographical, taxonomical andnomenclaturalstudies, and several new species have been described from Australia, Canada, Cyprus, Israel, Spain, and Turkey.
Morels resemble ahoneycombdue to the network of ridges with pits composing theircaps. Morels have a convoluted head/cap, and are varied in shape and habitat.
When gathering morels for the table, care must be taken to distinguish them from the poisonous "false morels", a term loosely applied to describeGyromitra esculenta,Verpa bohemica, and other morel lookalikes. Although false morels are sometimes eaten without ill effect, they can cause severe gastrointestinal upset, loss of muscular coordination (includingcardiac muscle), or even death.Incidents ofpoisoningusually occur when they are eaten in large quantities, inadequately cooked, or over several days in a row. False morels containgyromitrin, an organiccarcinogenicpoison, hydrolyzed in the body intomonomethylhydrazine(MMH).Gyromitra esculentain particular, has been reported to be responsible for up to 23% of mushroom fatalities each year inPoland.
The key morphological features distinguishing false morels from true morels are as follows:
Thefruit bodiesofMorchellaspecies are highlypolymorphic, varying in shape, color, and size. While in many cases they do not exhibit clear-cut distinguishing features microscopically, this has historically contributed to uncertainties in taxonomy.Discriminating between the various taxa described is further hindered by uncertainty over which of these are truly biologically distinct. Remarkably, some authors in the past had suggested that the genus contains as few as 3 to 6 species,while others recognised as many as 34.Efforts to clarify the situation and re-evaluate old classical names (such asMorchella elataand others) in accordance to current phylogenetic data have been challenging, due to vague or ambiguous original descriptions and loss ofholotypematerial.In 2012, the simultaneous description of several new taxa from Europe by Clowezand North America by Kuo and colleaguesresulted in severalsynonymitiesfurther complicating matters, until a transatlantic study by Richard and colleagues resolved many of these issues in 2014.The genus is currently undergoing extensive re-evaluation with regard to the taxonomic status of several species.
MorchellaDill. ex Pers. : Fr. was typified byChristiaan Hendrik Persoonin 1794,withMorchella esculentadesignated as thetype speciesfor the genus. Among early pioneers who took an interest in the genus, were mycologistsJulius Vincenz von KrombholzandÉmile Boudier, who, in 1834and 1897respectively, published several species and varieties, accompanied by meticulously illustrated iconographic plates. The seminal taxonMorchella elata, whose true identity still remains unresolved,was described byElias Friesin 1822, from a fir forest inSweden.Other classical, early-proposed names includeMorchella deliciosa, also described by Fries in 1822,Morchella semilibera, the half-free morel, originally described byde Candolleand sanctioned by Fries in 1822,Morchella vulgaris, which was recombined bySamuel Grayas a distinct species in 1821following aformaofM. esculentapreviously proposed byPersoon, andMorchella angusticeps, a large-spored species described by American mycologistCharles Peckin 1887.Morchella purpurascens, the purple morel, was first described byBoudieras a variety ofM. elatain 1897 based on an 1834 plate by Krombholz, and was recombined as a distinct species in 1985 by Emile Jacquetant.Morchella eximia, a globally-occurring fire-associated species was also described byBoudierin 1910.The old, widely applied nameMorchella conica,featuring in many field guides and literature across several countries, has been shown by Richard and colleagues to beillegitimate.
About 80 species ofMorchellawere described until the turn of the 21st century (per theIndex Fungorum), a number of which were later shown to be illegitimate or synonyms.As molecular tools became widely available in the new millennium, a revived interest in the genus commenced and several new species were proposed. In 2008 Kuo describedMorchella tomentosafrom burned coniferous forests in western North America.In 2010 Işiloğlu and colleagues describedMorchella anatolica,abasalspecies fromTurkeylater shown to be sister toMorchella rufobrunnea. A study by Clowez described over 20 new species in 2012,while later in the same year, another study by Kuo and colleagues described 19 species fromNorth America.However, several of these newly proposed names later turned out to be synonyms.An extensive taxonomical and nomenclatural revision of the genus provided by Richard and colleagues in 2014, applied names to 30 of the genealogical lineages recognized so far and clarified several synonymities.Also in 2014, Elliott and colleagues describedMorchella australianafromsclerophyllforests inAustralia,while Clowez and colleagues describedMorchella fluvialisfrom riparian forests inSpain.
In 2015, Loizides and colleagues clarified the taxonomy ofMorchella tridentina, a cosmopolitan species described under many names, and recombinedMorchella kakiicoloras a distinct species.Later in the same year, Clowez and colleagues describedMorchella palazoniifrom Spain,while Voitk and colleagues describedMorchella laurentianafromCanadaandMorchella eohespera, a cosmopolitan species present in several continents.In an extensive phylogenetic and morphological study fromCyprusin 2016, Loizides and colleagues added two moreMediterraneanspecies,Morchella arbutiphilaandMorchella disparilis, and resurrectedMorchella dunensisas an autonomous species.In the same year, Taşkın and colleagues described four of the previously unnamed phylospecies from Turkey:Morchella conifericola,Morchella feekensis,Morchella magnisporaandMorchella mediteterraneensis.
Earlyphylogeneticanalyses supported the hypothesis that the genus comprises only a few species with considerablephenotypicvariation.Subsequent multigenic DNA studies, however, have revealed more than a dozen genealogically distinct species inNorth Americaand at least as many inEurope.DNA studies revealed three discreteclades, or genetic groups, consisting of the "white morels" (Morchella rufobrunneaandM. anatolica), the "yellow morels" (M. esculentaand others), and the "black morels" (M. elataand others).The fire-associated speciesMorchella tomentosa, commonly known as the "gray morel", is distinct for itsfine hairson the cap ridges andsclerotia-like underground structures, and may also deserve its own clade based on DNA evidence.Within the yellow and black clades, there are dozens of distinct species, manyendemicto individual continents or regions.This species-rich view is supported by studies inWestern Europe,Turkey,Cyprus,Israel,China,Patagonia,and theHimalayas.
Earlyancestral reconstructiontests by O'Donnell and collaborators postulated awestern North Americanorigin of morels and the genus was estimated to have diverged from its closest genealogical relativesVerpaandDisciotisin the early Cretaceous, approximately 129 million years ago (Mya).This date was later revised by Du and collaborators, placing the divergence of the genus in the late Jurassic, approximately 154 Mya.However, neither of these reconstructions had includedMorchella anatolicain the analyses, whose phylogenetic placement remained at the time unresolved. Following genetic testing of isotype collection ofM. anatolicaby Taşkın and colleagues, this species was shown to nest in the ancestral /Rufobrunnea clade, together with the transcontinentalM. rufobrunnea.This cast doubts over the accuracy of the original reconstructions, since both species of the ancestral /Rufobrunnea clade are present in the Mediterranean, whileM. anatolicais altogether absent from North America.Updated ancestral area reconstructions by Loizides and colleagues using an expanded 79-species data set, have in 2021 refuted the previous hypothesis and designated theMediterranean basinas the most probable place of origin of morels.
Morels can be found in the temperateNorthern Hemisphere, in particular North America, Turkey, China, the Himalayas,India, andPakistan.
Yellow morels (Morchella esculentaand related species) are more commonly found underdeciduoustrees rather thanconifers, while black morels (M. elataand related species) are mostly found in coniferous forests,disturbed groundand recently burned areas.Morchella galilaea,and occasionallyM. rufobrunnea,appear to fruit in the autumn or winter months rather than spring, which is the typical fruiting season for morels. In the AmericanPacific Northwest, they can be found from April to August.
Efforts tocultivatemorels at a large scale have rarely been successful and the commercial morel industry relies on the harvest of wild mushrooms.
Although many species withinMorchellaexhibit continentalendemismand provincialism,several species have been phylogenetically shown to be present in more than one continent. So far, the list of transcontinental species includesM. americana,M. eohespera,M. eximia,M. exuberans,M. galilaea,M. importuna,M. populiphila,M. pulchella,M. rufobrunnea,M. semilibera,M. sextelata,M. steppicola, andM. tridentina.The reasons behind the widespread, cosmopolitan distribution of these species, are still puzzling. Some authors have hypothesized that such transcontinental occurrences are the result of accidental anthropogenicintroductions,but this view has been disputed by others, who suggested an old and natural distribution, at least for some of these species which appear to be linked to indigenous flora.Long-distance spore dispersal has also been suggested as a possibledispersalmechanism for some species, especially those belonging to fire-adaptedlineages.It has been suggested that the widespread but disjunct distribution of some morel species, especially early diverging lineages likeM. rufobrunneaandM. tridentina, may be the result of climatic refugia from theQuaternary glaciation.
The ecology ofMorchellaspecies is not well understood. Many species appear to formsymbioticorendophyticrelationships with trees,while others appear to act assaprotrophs.
Tree species associated withMorchellavary greatly depending on the individual species, continent, or region. Trees commonly associated with morels in Europe and across theMediterraneanincludeAbies(fir),Pinus(pine),Populus(poplar),Ulmus(elm),Quercus(oak),Arbutus(strawberry trees),Castanea(chestnut),Alnus(alder),Olea(olive trees),Malus(apple trees), andFraxinus(ash).In western North America morels are often found in coniferous forests, including species ofPinus(pine),Abies(fir),Larix(larch), andPseudotsuga(Douglas-fir), as well as inPopulus(cottonwood)riparianforests.Deciduous trees commonly associated with morels in the northern hemisphere includeFraxinus(ash),Platanus(sycamore),Liriodendron(tulip tree), dead and dyingelms,cottonwoods, and oldapple trees(remnants oforchards).Due to their springtimephenology(March–May), morels are hardly ever found in the vicinity of common poisonous mushrooms such as thedeath cap(Amanita phalloides), thesulphur tuft(Hypholoma fasciculare), or thefly agaric(Amanita muscaria).They can, however, occur alongsidefalse morels(GyromitraandVerpaspecies) and elfin saddles (Helvellaspecies), which also appear in spring.
CertainMorchellaspecies (M. eximia,M. importuna,M. tomentosaand others) exhibit apyrophilicbehaviour and may grow abundantly in forests which have been recently burned by afire.Moderate-intensity fires are reported to produce higher abundances of morels than low- or high-intensity fires.This is caused by the soil becoming more alkaline as the result ofwood ashcombining with water and being absorbed into the soil which triggers the morels to fruit.Alkaline soilconditions which trigger fruiting have been observed and exploited with small-scale commercial cultivation of morels.Where fire suppression is practiced, morels often grow in small numbers in the same spot, year after year. If these areas are overrun by wildfire they often produce a bumper crop of black morels the following spring. Commercial pickers and buyers in North America target recently burned areas for this reason. These spots may be closely guarded by mushroom pickers, as morels are widely regarded as adelicacyand often acash crop.
Due to the mushroom's prized fruit bodies, several attempts have been made to grow the fungus in culture. In 1901, Repin reported successfully obtaining fruit bodies in a cave in which cultures had been established in flower pots nine years previously in 1892.
More recently, small-scale commercial growers have had success growing morels by using partially shaded rows of mulched wood. The rows of mulch piles are inoculated with morel mushroom spores in a solution of water and molasses which are poured over the piles of mulch and then they are allowed to grow undisturbed for several weeks. A solution of wood ashes mixed in water and diluted is subsequently poured over the rows of wood mulch which triggers fruiting of the morels. Morels are known to appear after fires and the alkalinity produced by wood ash mixed with water initiate fruit body formation for most species of morels.
In 2021 it was announced that indoor cultivation of black morels had been successfully achieved after decades of research and experimentation with methods byThe Danish Morel Project. The project has been able to cultivate 20 lbs of morels per square yard or around 10 kg per square metre with cost estimates expected to be similar to producing white button mushrooms (Agaricus bisporus). Previous attempts at cultivation had managed to producesclerotiabut encountered issues in getting them to reliably fruit. One of the breakthroughs with this project was growing them in a climate controlled environment in conjunction with grass which is involved in stimulating fruiting in the morel mycelium. Cultivation in this manner has been noted to produce superior morels for culinary uses since they can be assured to be insect, slug and dirt free and therefore do not need to be washed and cleaned like foraged morels. Since washing morels can negatively impact the texture, reliable cultivation may result in more versatility with this ingredient in the kitchen as well as making the delicacy more affordable and accessible.
The consumption ofMorchellaspecies can have adverse effects. In 2023, a Montanasushirestaurant serving them was linked to 51 people who experiencedgastrointestinal illness, with two reported deaths and three other hospitalizations.The consumption of raw morels in particular is advised against.An unknown toxincan be neutralized via cooking.Additionally, cooked morels can reportedly cause symptoms ofupset stomachwhen consumed with alcohol.
When eating this fungus for the first time, it is advised to consume a small amount to minimize any allergic reaction. As with all fungi, morels for consumption must be clean and free of decay. Morels growing in oldappleorchards previously treated with the deprecated insecticidelead arsenatemayaccumulatelevels of toxicleadandarsenicthat are unsuitable for human consumption.
Morels, "almost universally associated with spring," can be found in many habitats. Morel may be more likely to fruit during a period of increasing heat following a chilly period, a preference which is credited for their abundance in areas with cold winters.
Black morels (Morchella elata) are often found on land that has been disturbed by logging burning.
Raw morel mushrooms are 90% water, 5%carbohydrates, 3%protein, and 1%fat. A 100 gram reference amount supplies 31calories, and is a rich source ofiron(94% of theDaily Value, DV),manganese,phosphorus,zinc, and vitamin D (34% DV, if having been exposed to sunlight or artificialultraviolet light). Raw morels contain moderate levels of severalB vitamins(table).
They have been called "prized delicacies...they 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 are a feature of many cuisines, includingProvençal.Their flavor is prized bychefsworldwide, with recipes and preparation methods designed to highlight and preserve it.As with mostedible fungi, they are best when collected or bought fresh. They are sometimes added to meat and poultry dishes and soups, and can be used aspastafillings.As morels are known to containthermolabiletoxins, they must always be cooked before eating.
Morels can be preserved in several ways: They can be'flash frozen'by simply running under cold water or putting them in a bucket to soak for a few minutes, then spread on abaking trayand placed into a freezer. After freezing, they keep very well with the frozen glaze for a long time in airtight containers. However, when thawed they can sometimes turn slightly mushy, so they are best frozen aftersteamingorfrying. Due to their natural porosity, morels may contain trace amounts of soil which cannot be easily washed out. Any visible soil should be removed with a brush, after cutting the body in half lengthwise, if needed. Mushroom hunters sometimes recommend soaking morels in a bowl of salt water briefly prior to cooking, although many chefs would disagree.
Dryingis a popular and effective method for long-term storage, and morels are widely available commercially in this form. Anyinsect larvaewhich might be present in the fruit bodies usually drop out during the drying process.Dried morels can then be reconstituted by soaking for 10–20 minutes in warm water or milk, and the soaking liquid can be used as stock.
The flavor of morels is not just appreciated by humans; inYellowstone National Park, black morels are also known to be consumed bygrizzly bears(Ursus arctos horribilis).
Morel hunting is a common springtime activity. Mushroom collectors may carry a mesh collecting bag, so the spores can scatter as one carries the harvest.
Every spring, hundreds of morel enthusiasts gather inBoyne City, Michiganfor the National Morel Mushroom Festival, a century-old event.As one observer stated, "if there is a modern, North American reenactment ofGeoffrey Chaucer'sCanterbury Talesthis is it."Other festivals and hunting competitions inNorth Americainclude the Illinois State Morel Mushroom Hunting Championship, the Ottawa Midwest Morel Fest and the Mesick Michigan Mushroom Festival.
Morchellaspecies have been called by many local names; some of the more colorful includedryland fish, because when sliced lengthwise then breaded and fried, their outline resembles the shape of a fish;hickory chickens, as they are known in many parts ofKentucky; andmerkelsormiracles, based onfolklore, of how a mountain family was saved from starvation by eating morels. In parts ofWest Virginia, they are known asmolly moochers,muggins, ormuggles. Due to the partial structural and textural similarity to some species ofPorifera(sponges), other common names for any true morel aresponge mushroomandwafflemushroom. In the Appalachian woodlands, morels have also been calledhaystacks, orsnakeheads.TheFinnishvernacular namehuhtasieni, refers tohuhta, area cleared for agriculture by the slash and burn method.
The scientific name of the genusMorchellaitself, is thought to have derived frommorchel,an oldGermanword close to "Möhre", carrot or beet, due to similarity in shape.