White Morel (Morchella deliciosa)
White Morel (Morchella deliciosa)
White Morel (Morchella deliciosa) is a spring-fruiting ascomycete native to Europe, recognized by its pale cream honeycomb cap and the fully hollow interior shared by all true morels. It is the species behind the discovery of (S)-morelid, a previously unknown taste compound named for this mushroom—found nowhere else in the food world before 2005. No reproducible fruiting body cultivation protocol exists for this species; it is available as liquid culture for mycelial research, agar expansion, and experimental substrate work.
Morchella deliciosa Fr. — Family Morchellaceae — Order Pezizales
White Morel (Morchella deliciosa) sits at a unique intersection: it is one of the most prized culinary mushrooms in Europe, the source of a flavor compound discovered nowhere else in the food world, and one of the most taxonomically misidentified fungi in the scientific literature. Understanding this species requires unpacking a century of naming confusion, a revolution in molecular phylogenetics that reshaped the entire genus, and a cultivation reality that is more complex—and more honest—than most guides acknowledge. This article covers the full science.
What Is the White Morel (Morchella deliciosa)?
White Morel (Morchella deliciosa) is a spring-fruiting ascomycete—meaning it belongs to the sac fungi (Ascomycota) rather than the gilled and bracket fungi (Basidiomycota) that most people think of when they picture mushrooms. Its fruiting body consists of a pitted, honeycomb-like cap (the pileus) attached directly to a hollow white stem, with no gill surface and no partial veil. The cap surface is covered by a network of deep pits and ridges, with the ridges tending to darken in age—a field character that distinguishes this species within the broader morel group. Young specimens are pale cream to whitish; mature caps shift toward gray-brown to pale ochre.
The name “white morel” is genuinely ambiguous in English, and this matters for anyone researching this species. In North America, “white morel” is most commonly applied to Morchella americana—a different species entirely. Morchella deliciosa is fundamentally a European species, confirmed as such by multilocus molecular phylogenetics since 2012. Historical application of the name to North American specimens was erroneous. The USDA lists “Delicious Morel” as the formal English common name. This article uses “White Morel (Morchella deliciosa)” throughout to be precise about the species being discussed.
What makes White Morel (Morchella deliciosa) scientifically distinctive is its taste chemistry. In 2005 and 2006, researchers at the Technical University of Munich—using molecularly unverified but morphologically identified M. deliciosa fruiting bodies—discovered a previously unknown glycoside named (S)-morelid: a compound that had never been reported in any food product before and that contributes both umami character and synergistic flavor amplification. This discovery is unique to this species in the published literature.
The defining scientific fact about White Morel (Morchella deliciosa): It is the only food source from which (S)-morelid—a previously undescribed glycoside that enhances both umami and salt perception—has ever been isolated and characterized. The compound was named directly after this mushroom.
Interested in working with this species? Out-Grow carries a liquid culture.
White Morel (Morchella deliciosa) Liquid CultureHow Is White Morel (Morchella deliciosa) Classified?
The accepted name is Morchella deliciosa Fr., first validly published by Elias Magnus Fries in 1822 in Systema Mycologicum 2(1):8. Because Fries both described and sanctioned the name in the same work, M. deliciosa is its own basionym—there is no earlier epithet being recombined. Index Fungorum registration identifier: 203775. MycoBank identifier: 203775.
| Rank | Name |
|---|---|
| Domain | Eukaryota |
| Kingdom | Fungi |
| Phylum | Ascomycota |
| Class | Pezizomycetes |
| Subclass | Pezizomycetidae |
| Order | Pezizales |
| Family | Morchellaceae |
| Genus | Morchella Dill. ex Pers. |
| Species | Morchella deliciosa Fr. |
The “Morchella conica” Naming Problem
For much of the 20th century, the name Morchella conica was used interchangeably with M. deliciosa and related conical black morels. Some authors treated M. conica as the correct species name and M. deliciosa as subordinate. The 2015 nomenclatural revision by Richard et al.—using multilocus phylogenetics and designating a formal lectotype for M. deliciosa—determined that Morchella conica is illegitimate at the species rank, strengthening the use of M. deliciosa as a valid species name. Any literature you encounter using “M. conica” before about 2015 may be referring to this species, a closely related species, or a composite of several.
The 66% GenBank Misidentification Problem
A 2012 analysis of 865 Morchella sequences found that at least 66% of named sequences in GenBank were misidentified. This is a published, peer-reviewed finding with direct implications for reading the morel literature: any study claiming to work with M. deliciosa that predates about 2012 and used only ITS sequencing for identification should be treated with significant caution. This includes phenolic content, nutritional, and pharmacological studies. The most reliable data in this article comes from molecularly verified specimens identified using multilocus methods.
Synonyms and Why They Exist
| Synonym | Authority | Reason |
|---|---|---|
| Morilla deliciosa | (Fr.) Quél. 1892 | Generic recombination by Quélet |
| Morchella conica var. deliciosa | (Fr.) Cetto 1988 | Subordinated as variety of M. conica |
| Morchella pyramidalis | Chevall. | Morphological synonym |
| Phalloboletus deliciosus | (Fr.) Kuntze | Obsolete generic placement |
| Morchella deliciosa var. elegans | Boud. | Intraspecific variety |
How Do You Identify White Morel (Morchella deliciosa)?
White Morel (Morchella deliciosa) belongs to the Elata Clade—the black morels—a group of approximately 33–37 phylospecies that represents the most taxonomically complex section of the genus. Morphological identification to species level within this group is genuinely difficult even for expert mycologists; confident species identification requires multilocus molecular data. That said, identification of the group “true morel” is straightforward and critical for safe foraging.
The single most important identification feature for the Morchella genus is the completely hollow interior. Slice any suspected morel lengthwise: a true morel is hollow from the very top of the cap down through the stem to the base. The cap is also fully attached to the stem at the base with no free skirt. These two features together—hollow interior, cap attached at base—distinguish true morels from the dangerous lookalikes described below.
Lookalike Species
Gyromitra esculenta — False Morel
Critical safety hazard. Cap is brain-like or saddle-shaped—wrinkled and convoluted, NOT pitted in a honeycomb pattern. Cap is NOT fully attached to the stem. Interior is chambered, not simply hollow. Contains gyromitrin, which converts to monomethylhydrazine in the body—potentially lethal. Never eat Gyromitra.
Verpa bohemica — Wrinkled Thimble Cap
Safety concern. Cap resembles a morel at first glance but hangs “free” from the stem, attached only at the very top like a thimble—not at the base. Cap is wrinkled or folded, not pitted in a true honeycomb. Causes illness in some people when eaten in quantity.
Morchella elata
Close relative in the Elata Clade. Ridges typically darker even when young; build more robust; often associated with conifers in mountain habitats. Cannot be reliably separated from M. deliciosa by morphology alone—multilocus sequencing required. Both are edible true morels when cooked.
Morchella importuna
Commercially cultivated black morel; often found in wood chips, disturbed soil, and garden beds. Ridges typically darker. Morphologically similar to M. deliciosa; ITS sequencing alone is insufficient to separate them within the Elata Clade—multilocus data required.
Morchella americana
The most common North American “white morel.” Occurs on a different continent from M. deliciosa in the wild. For cultivators using culture from North American vendors, verify species identity. Both are edible true morels when properly cooked.
Morchella eximia
Wider cap; ridges characteristically orange-brown; appears in burned or disturbed habitats. Spore size overlaps with M. deliciosa; multilocus sequencing provides reliable separation. Edible true morel when cooked.
ITS barcoding is insufficient within this group. A 2012 study analyzing 865 Morchella sequences found that ITS alone failed to resolve 12 of 22 species in the Elata Subclade—the group containing M. deliciosa. Confident species-level identification requires multilocus sequencing: ITS + LSU + RPB2, or the full five-marker GCPSR panel. A specimen identified as “M. deliciosa” by ITS alone may be M. importuna, M. elata, or one of several unnamed phylospecies.
Where Does White Morel (Morchella deliciosa) Grow?
White Morel (Morchella deliciosa) is a European endemic. The historical application of this name to North American morel specimens has been determined to be erroneous by multilocus molecular data; those specimens are now assigned to other species, primarily Morchella americana. Confirmed occurrence records for molecularly verified M. deliciosa come from Russia (Saint Petersburg region, Leningrad Oblast—near ash, elm, and poplar), Poland (Silesian Beskids, Ojców National Park area), France (reference sequences in GenBank), and Turkey (Isparta province, near Juniperus spp. and Abies spp.).
The Elata Clade, which contains M. deliciosa, shows approximately 70% of species occurring in coniferous forests. M. deliciosa specifically is documented from both deciduous associations (ash, elm, poplar) and coniferous/mixed contexts (Juniperus, Abies). In the Russian records, the mushrooms occurred in forest parks along riverbanks—suggesting a preference for moist, nutrient-rich woodland soils. Calcareous (lime-rich) soil preference is documented for the genus. Seasonal fruiting: late April to early June in northwestern Russia and Poland, tracking soil temperature rather than calendar date, with optimal fruiting typically when soil temperatures reach 7–15°C.
The Unresolved Trophic Mode
Unlike almost every other major edible mushroom—which is clearly either saprotrophic (oyster mushrooms, shiitake) or ectomycorrhizal (porcini, chanterelles)—morels in general have a trophic mode that remains genuinely unresolved. Stable isotope evidence suggests “largely saprophytic” behavior; laboratory studies have documented mycorrhiza-like structures between Morchella elata and larch roots; and at least one morel species (M. sextelata) has been shown to infect grass roots as an endophyte. Current scientific consensus is that Morchella likely encompasses species spanning all three modes, and that a single trophic label for the genus—or for M. deliciosa specifically—is not scientifically defensible. For cultivators, this is directly relevant: if M. deliciosa has a stronger mycorrhizal dependency than the commercially cultivated species, fruiting body production without a plant host may not be achievable.
Can You Cultivate White Morel (Morchella deliciosa)?
This is the most important question to answer honestly. No published, peer-reviewed fruiting body cultivation protocol exists for White Morel (Morchella deliciosa). The liquid culture and mycelial culture for this species are real and viable; growing the mycelium on agar or grain is achievable. Producing fruiting bodies with a reproducible protocol is not documented for this species in any accessible scientific literature. This is not unique to Out-Grow—no vendor or researcher has published a working fruiting protocol for M. deliciosa.
This is a meaningful distinction. It places White Morel in a different category from commercially cultivated morels like Morchella importuna and M. sextelata—species for which Chinese large-scale field cultivation methods have been developed, tested, and published. M. deliciosa, as a European Elata Clade species, has not been subjected to equivalent cultivation research.
What Has Been Successfully Cultivated
To understand where M. deliciosa stands, it helps to know the species that have crossed the cultivation threshold:
Agar and Liquid Culture Behavior
Morel mycelium grows on agar and in liquid culture. The best-performing media for morel mycelial growth are Malt Extract Agar (MEA) and Potato Dextrose Agar (PDA); coconut water-enriched MEA has been shown to promote the highest mycelial density and sclerotia formation in a multi-species morel study. Optimal temperature is approximately 20–22°C for vegetative mycelial growth; temperatures above 25°C are generally detrimental. Preferred pH is 7–8, consistent with the slightly alkaline soil preference documented for the genus.
Morel mycelium grows slowly relative to most cultivated basidiomycetes, which creates vulnerability to faster-growing contaminants. Trichoderma (green mold) and Penicillium are the primary agar contaminants; bacterial wet rot is the primary liquid culture failure mode. Wild-tissue isolates may carry bacterial endophytes that complicate clean culture work.
The Sclerotia Bottleneck
Unlike basidiomycete mushrooms, morels must pass through a sclerotia stage—the formation of compact, melanized resting structures that function as nutrient reserves—before any fruiting body development can occur. Sclerotia formation and the subsequent sclerotia-to-ascomata (fruiting body) transition is the major developmental bottleneck in morel cultivation and the least understood aspect of morel biology, even for the commercially cultivated species. The specific signals that trigger this transition in M. deliciosa are completely undocumented.
What Liquid Culture Can Realistically Be Used For
Agar Expansion
Inoculating new MEA or PDA plates to maintain and expand the culture. The primary functional use. Allows strain preservation, morphological observation, and selection work at 20–22°C.
Grain Spawn Production
Inoculating sterilized grain (rye, wheat, millet) to produce grain spawn for potential soil-bed substrate trials. Slower colonization than basidiomycetes; strict sterile technique required.
Experimental Substrate Trials
Inoculating controlled soil/compost beds to test for mycelial colonization and sclerotia formation under defined conditions. A legitimate research application that could contribute to the cultivation literature.
Mycelial Biomass Production
Submerged fermentation for biomass extraction—for polysaccharide research, nutritional analysis, or taste compound characterization. Morchella mycelium produces active metabolites in liquid culture.
Genetic Material Preservation
Maintaining viable mycelium for future research, strain banking, or genetic analysis. Given the scarcity of molecularly verified M. deliciosa material, culture preservation has genuine research value.
Fruiting Body Production
Not currently achievable with a published, reproducible protocol for this species. Experimental attempts remain a legitimate research frontier, but no cultivation protocol has been peer-reviewed or widely replicated for M. deliciosa.
About the Out-Grow White Morel Liquid Culture
Out-Grow’s 12cc White Morel (Morchella deliciosa) liquid culture syringe contains actively growing mycelium suspended in a sterile nutrient solution. This culture is appropriate for agar expansion, grain spawn production, and experimental substrate inoculation under controlled conditions. Store in a cool, dark place until use; refrigeration extends viability.
This culture is sold for research, experimental cultivation, and hobbyist mycology. Because no peer-reviewed fruiting protocol exists for this species, it is most accurately described as a research-grade starting point for those interested in contributing to the frontier of morel cultivation science—or in maintaining the mycelium for study, biomass production, and agar work. The science does not currently support expectations of fruiting body production from this culture, and we say so plainly.
What Bioactive Compounds Does White Morel (Morchella deliciosa) Contain?
White Morel (Morchella deliciosa) is the subject of the most rigorous taste chemistry research ever conducted on a morel species—two consecutive peer-reviewed studies using taste dilution analysis (TDA) methodology on M. deliciosa fruiting bodies specifically. These studies yielded a genuinely novel discovery: a taste compound found nowhere else in the food world before 2005. The evidence quality for taste compounds is unusually high for this species. Evidence for other compound classes is more limited.
(S)-Morelid
A previously unknown glycoside—(S)-malic acid 1-O-β-D-glucopyranoside—first isolated from this species. Taste threshold: 6.0 mmol/L. Functions as an umami amplifier and synergist: it enhances the taste activity of both monosodium glutamate and sodium chloride. Had never been reported in any food product before its discovery in M. deliciosa in 2005. Named for this mushroom.
Peer-reviewed, M. deliciosa specificγ-Aminobutyric acid (GABA)
Identified as the chemical inducer of the distinctive mouth-drying and mouth-coating sensation of morel extract. Taste threshold: 0.02 mmol/L—among the most potent taste-active compounds identified in this species. Data from molecularly unverified but morphologically identified M. deliciosa.
Peer-reviewed, M. deliciosa specificL-glutamic & L-aspartic acid
Standard umami contributors; confirmed as key organoleptic compounds in the taste reconstitution study. Together with (S)-morelid, malic acid, citric acid, acetic acid, and GABA, they form the core taste profile of morel extract. A biomimetic reconstitute of these compounds reproduced authentic morel taste in triangle tests.
Peer-reviewed, M. deliciosa specificPhenolics (total)
135.80 mg GAE/g dry weight—from one molecularly verified specimen (HT682, Isparta, Turkey; ITS-confirmed). This was the lowest value among 6 molecularly confirmed Morchella species in the same study. DPPH: 0.27 mmol TE/g DW. FRAP: 0.61 mmol TE/g DW.
Single molecularly verified specimenFatty Acids
Linoleic acid (C18:2, PUFA): 52.09%; oleic acid (C18:1, MUFA): 36.15%; palmitic acid (C16:0, SFA): 7.83%. Total UFAs/SFAs ratio: 8.70—substantially exceeding the WHO-recommended minimum of 1.6. Data from the same molecularly verified HT682 specimen.
Single molecularly verified specimenPolysaccharides
No polysaccharide characterization study specific to M. deliciosa has been published. Genus-level data from M. esculenta documents beta-glucan-type structures with antioxidant, immunomodulatory, and hepatoprotective bioactivities in animal models. These findings cannot be directly attributed to this species.
Research gap — genus data onlyVolatile Aroma Compounds
No GC-MS or GC-olfactometry study has characterized the volatile profile of M. deliciosa specifically. Analogous data from M. esculenta and M. importuna suggests 1-octen-3-ol and phenol are likely dominant, but this has not been confirmed for this species. A research gap explicitly noted in the literature.
Research gap — related species onlycis-3-Amino-L-proline
An unusual non-protein amino acid isolated from Morchella esculenta fruiting bodies and mycelia. Its presence in M. deliciosa has not been confirmed but is plausible given phylogenetic proximity. Not yet characterized for pharmacological activity in this species.
Plausible, unconfirmed for this speciesEvidence calibration: The taste chemistry data for White Morel (Morchella deliciosa) is genuinely species-specific and high-quality—a rare situation for this genus. The phenolic and fatty acid data come from a single molecularly verified specimen from one location; they represent accurate findings but not a comprehensive nutritional profile. For all other compound classes, data is either absent or extrapolated from related species. No human clinical studies exist for any Morchella species.
Is White Morel (Morchella deliciosa) Safe to Eat?
White Morel (Morchella deliciosa) is classified as an edible species and is consumed widely in Europe without documented case reports of illness from properly cooked specimens. However, like all true morels, it must be thoroughly cooked before eating. This is not a general caution—it is a safety-critical requirement with recent fatal consequences in a documented outbreak.
In March–April 2023, 51 people became ill after consuming raw or undercooked Morchella sextelata (DNA-confirmed) at a restaurant in Bozeman, Montana. Three people were hospitalized. Two people died. A clear dose-response relationship was identified: people who ate more raw morel experienced more severe illness. No illness was documented from fully cooked mushrooms from the same lot at other restaurants. The CDC and FDA both issued formal guidance recommending thorough cooking of all morel mushrooms. The specific toxin responsible has not been isolated—it appears to be heat-labile, and the mechanism is distinct from Gyromitra (false morel) toxicity.
All morels, including White Morel (Morchella deliciosa), must be cooked thoroughly before eating. Raw or undercooked morel consumption caused 2 deaths and 3 hospitalizations in a 2023 CDC-documented outbreak. The toxin is heat-labile and appears to be destroyed by thorough cooking. Slice morels lengthwise before cooking to ensure even heat penetration. Never consume any morel raw.
At properly cooked doses, M. deliciosa has no documented toxic compounds or illness cases. The fruiting body is not toxic when fully cooked. No drug interactions or special population contraindications specific to morels have been identified in the peer-reviewed literature. The hollow interior of morels provides habitat for insects—slice vertically before preparation and check for inhabitants.
What Makes White Morel (Morchella deliciosa) Remarkable?
(S)-Morelid: A Compound Named for This Species
The 2005 and 2006 studies from Thomas Hofmann’s group at TU Munich represent the only peer-reviewed taste chemistry research ever conducted specifically on M. deliciosa fruiting bodies. They discovered (S)-morelid—a glycoside not previously reported in any food on Earth—and then showed it not only contributes umami character but amplifies the activity of both MSG and NaCl. The compound is named for this mushroom. This is the chemical reason morels are so effective as a flavor foundation in sauces, stocks, and risottos: a synergistic taste compound unique to the species.
The Trophic Mode Mystery
Morchella species appear to operate across a spectrum including saprotrophy, facultative mycorrhizal associations, and endophytic relationships—depending on species, developmental stage, and environmental context. This is ecologically unusual: morels may be the only major genus of edible mushrooms where the nutritional strategy is genuinely unresolved. For M. deliciosa specifically, no isotopic or molecular study has examined whether it is saprotrophic, mycorrhizal, or both.
Continental Endemism in a Spore-Dispersed Organism
Only 7 of approximately 65 recognized Morchella phylospecies occur on more than one continent. M. deliciosa is a European endemic. This strong endemism is biogeographically puzzling for a spore-dispersed fungus whose spores are microscopic and theoretically capable of long-distance dispersal. The evolutionary history involves origins in western North America in the late Jurassic, spread across ancient land bridges, and a mid-Miocene to Pleistocene European radiation for the Elata Clade.
The Sclerotia Life Cycle Stage
Unlike virtually all cultivated basidiomycete mushrooms, morels must produce sclerotia—compact, melanized resting structures that function as nutrient reserves—as an obligate intermediate step before any fruiting body development. The sclerotia-to-fruiting body transition is the central unsolved problem of morel cultivation biology. Even for commercially cultivated species, the specific molecular and environmental signals that trigger this transition are not fully characterized. For M. deliciosa, this pathway is entirely undocumented.
The ITS Misidentification Crisis
The revelation that at least 66% of named Morchella sequences in GenBank are misidentified creates a significant interpretive problem for the entire morel literature. Many published studies claiming findings for specific morel species—including pharmacological, nutritional, and phenolic studies—may have been conducted on different species. This makes M. deliciosa one of the most under-characterized edible mushrooms relative to its culinary status: genuine species-specific data is scarce.
Fire Ecology and Within-Clade Niche Divergence
Within the Elata Clade containing M. deliciosa, several species have independently evolved fire-adapted traits—producing abundant fruiting bodies in the spring following a forest fire. M. deliciosa is NOT fire-adapted; it occurs in undisturbed forest habitats, growing near ash, elm, and poplar. This within-clade ecological niche divergence illustrates how a single evolutionary lineage can produce species with dramatically different ecological strategies across the same geographic region.
Also available as a culture plate from Out-Grow.
White Morel (Morchella deliciosa) Culture PlateFrequently Asked Questions About White Morel (Morchella deliciosa)
Is White Morel (Morchella deliciosa) the same as the common North American white morel?
No. In North America, “white morel” most commonly refers to Morchella americana (formerly called M. esculentoides), a different species entirely. Morchella deliciosa is a European endemic—the historical application of this name to North American specimens was determined to be erroneous by multilocus molecular phylogenetics. If you are foraging in North America and find what you call a “white morel,” it is almost certainly not M. deliciosa. The two species are genuinely different organisms with separate geographic ranges.
What is (S)-morelid and why does it matter?
(S)-Morelid is a glycoside—specifically (S)-malic acid 1-O-β-D-glucopyranoside—first isolated from White Morel (Morchella deliciosa) fruiting bodies by researchers at the Technical University of Munich and published in 2005. It had never been reported in any food product before. What makes it particularly interesting is its synergistic function: (S)-morelid not only contributes its own umami-like taste but amplifies the taste activity of both monosodium glutamate and sodium chloride. A follow-up study in 2006 confirmed through taste reconstitution that (S)-morelid is a key contributor to the authentic morel flavor profile. This compound is named for the species and represents the best evidence of what makes morel flavor chemically distinctive.
Can White Morel (Morchella deliciosa) be cultivated to produce fruiting bodies?
Not with any published, peer-reviewed protocol. Large-scale morel cultivation works for Morchella importuna and M. sextelata—two different species developed for commercial production in China. M. deliciosa has not been successfully brought through the full cultivation cycle (sclerotia formation → sclerotia germination → fruiting body development) in any documented experiment. The liquid culture can be used for agar expansion, grain spawn production, mycelial biomass work, and experimental substrate trials—these are genuine and legitimate uses. Fruiting body production remains an open research frontier for this species.
Are morels safe to eat raw?
No. Raw morel consumption caused 2 deaths and 3 hospitalizations in a 2023 CDC-documented outbreak in Montana. All true morels—including White Morel (Morchella deliciosa)—should be considered toxic when raw or undercooked. The specific toxin has not been isolated but appears to be heat-labile and destroyed by thorough cooking. The FDA and CDC both recommend cooking all morel mushrooms before eating. Properly and thoroughly cooked morels have a strong safety record with no documented illnesses in the peer-reviewed literature.
Why is identifying Morchella deliciosa to species level so difficult?
White Morel (Morchella deliciosa) belongs to the Elata Clade—the black morels—a group of approximately 33–37 phylospecies. ITS barcoding, the most common molecular identification tool, cannot reliably separate 12 of 22 species within this clade. The only reliable identification method for M. deliciosa requires multilocus sequencing: ITS + LSU + RPB2, or the full five-marker GCPSR panel matched against the Morchella MLST database. A 2012 study found that at least 66% of named Morchella sequences in GenBank are misidentified, meaning much of the published literature on specific morel species must be read with caution.
What is the difference between true morels and false morels?
True morels (Morchella spp.) are distinguished from dangerous false morels by two features that can be checked in the field: first, the cap surface of a true morel has a genuine pitted honeycomb pattern—not wrinkled, folded, or brain-like. Second, the interior of a true morel is completely hollow from the top of the cap down through the stem to the base. False morels (Gyromitra spp.) have wrinkled, irregular caps and chambered (not simply hollow) interiors, and contain gyromitrin—a compound that can cause fatal poisoning. Verpa bohemica (wrinkled thimble cap) has a cap attached only at the top rather than fully at the base. Slice any suspected morel lengthwise: if it is not completely hollow throughout, do not eat it.