Fungi can be found in some otherworldly shapes and forms. We've compiled six of the spookiest examples to haunt your imagination this Halloween
Dead man's fingers (Xylaria polymorpha)
This macabre fungus, which grows in palmate clusters of black and warty “fingers”, could easily be mistaken for the rotting hand of a corpse emerging from the soil. It’s found, after all, in shady woodlands — a favoured spot to conceal a body.
These ghoulish digits, known as stroma, can grow from 3cm to 8cm and you may have stepped over them many times without realising. Their rough black “skin”, comprised of “flasks” from which spores are produced, makes them hard to spot amid dark leaf litter.
The polymorpha of this fungus’s scientific name refers to the many forms its fruiting body can take. At points in its life-cycle, it can also appear an equally corpse-like green or grey, and can be white-tipped.
Keep your eyes peeled for this saprophyte tickling at your ankles as you pass the stumps of dead beech and occasionally other buried hardwoods, from which it extracts polysaccharides.
Devil's tooth fungus (Hydnellum Peckii)
This gory beauty of a mushroom forms into pinkish-white stumps, which resemble a tooth, and exudes striking, deep red guttation droplets. Its unusual bloody sap contains a chemical compound called atromentin, which has similar anticoagulant properties to heparin (Elkhateeb, Daba, Elnahas & Thomas, 2019).
There are other unusual features that add to the impression that this mushroom is a manifestation from the underworld. Rather than having gills or pores, Hydnellum peckii is a hydnoid fungus, and its underside is covered in small teeth or spines, which produce the spores. In younger specimens, the cap is enveloped with fine hairs, which creates a velvety zoomorphic feel.
Despite its fiendish appearance, Hydnellum peckii is a particularly beneficial mycorrhizal (symbiotic) species — categorised as an ectomycorrhizal. It forms symbiotic relationships with mature coniferous trees, wrapping its hyphae around their feeder roots to facilitate the transfer of nutrients. It prefers mountainous or subalpine ecosystems and as a result is a rare find in the UK, typically only seen in Scotland, particularly in the Caledonian forests.
Zombie fungi (Cordyceps and Ophiocorduceps spp.)
It doesn’t get much more ghoulish than a zombie insect being piloted to its death by a fungus.
There are over 400 species in the genus Cordyceps, many of which parasitise insects and other arthropods. A further 200 species, some with the ability for "mind control", are categorised as Ophiocordyceps, such as Ophiocordyceps unilateralis, famed for creating zombie ants in tropical rain forests.
In Britain, you are most likely to come across the Scarlet Caterpillarclub (Cordyceps militaris, pictured), which parasitises moth and butterfly pupae below the soil, before a 1cm-8cm bright orange-red fruiting body emerges.
Unlike most of the other fiendish fungi in this list, Cordyceps militaris is considered an edible and has a long tradition of medicinal use in Asian cultures, where it is thought to be revitalising. While Cordyceps militaris may not quite bring you back from the dead, it has been shown to have ergogenic, immunostimulating, antitumor, antioxidant, anti-inflammatory, antiviral, neuroprotective and hypolipemic properties (Jędrejko, Lazur and Muszyńska, 2021).
The yellow waspclub fungus (Ophiocordyceps forquignonii) is also known to parasitise insects in Britain. It's thought to cause flies to bury themselves into leaf litter, where the fungus can more easily spread. Meanwhile, if you've ever seen a ghostly cellar spider (Phlocus sp. ) — an all-white version of that delicate, long-legged inhabitant of damp rooms — the culprit is another fungus in the Cordycipitaceae family, Engyodontium aranearum, which causes 100% mortality.
Bleeding fairy helmet (Mycena haemotopus)
While mushroom-hunters in the US can seek out the eerily bioluminescent Jack O’Lanterns (Omphalotus olearius), those of us in the UK have to settle for the weak glow of the bleeding foot bonnet, also known as bleeding mycaneau and bleeding fairy helmet. Where this mushroom trumps its American counterpart for Halloweenish effect, however, is in the dramatic red latex it bleeds when cut.
This creatively-named fungi does look like a malign associate of the fairy folk, growing in delicate, pinkish-purple clusters on the rotting wood of deciduous trees, particularly oak. It’s common throughout Britain where it can usually be found between June and November.
Unsurprisingly, given its characteristics, this fungi is chemically interesting. Its latex “blood” contains the unique alkaloid pigment haematopodin B. Meanwhile, its low-level bioluminescence — which may not be visible to the dark-adjusted human eye — comes from the presence of the diabollically-named luciferase. Luciferases are enzymes which produce light when they oxidise their substrate and in mushrooms they most commonly appear in the bonnet species (Mycenae), which account for at least 68 of the 81 known bioluminescent fungi (Ke et al., 2020).
Weeping widow (Lacrymaria lacrymabunda)
This mushroom is the fungal world's ultimate goth chick.
Both its English and scientific names (lacry is latin for tears) are inspired by the ethereal, spore-stained black droplets that weep from its gills when damp.
When it first emerges, these gills are covered in a cobweb-like veil, which then forms a delicate fringe around the cap. To complete the effect, this inhabitant of grasslands, which prefers disturbed soils, is also prone to emerging in graveyards. It appears from March until well into the gloomy mists of autumn, with its season ending around November.
Weeping widows are members of the family Psathyrellaceae, which includes other dark-spored mushrooms, although unfortunately it doesn't have the tendency to auto-digest its fruiting bodies into black ooze like some of its compatriots. Those who enjoy looking at spores, however, can admire its particularly gothic examples, which are jet black and heavily ornamented.
Witches' Butter (Exidia glandulosa)
As the dank, dark, autumn and winter months close in, this black, slimy, jelly fungus appears more frequently on dead logs in the woods.
It is gelatinous when wet but shrivels, like a wizened hag, into an olive-brown warty crust in dry weather, only to revive once it rains. While it can appear as individual fruiting bodies of around 3cm, it can also cluster, smothering rotting branches.
One folk belief associated with this fungus is that that it was possible to counteract the effects of witchcraft by throwing it onto a blazing fire. There are also Eastern European legends equating the appearance of witches’ butter on the gateposts of dwellings with a sign that the household was under a witch’s spell. Allegedly, the magic could be thwarted by puncturing the fungus to allow the evil to escape.
Exidia glandulosa is not to be confused with another, rather more sunny, jelly fungus, the ochre-coloured Tremella mesenteric, which goes by the same common epithet. While Tremella mesenteric is closer in appearance to butter, it’s a bit less witchy, and is considered a low-culinary-value edible.
Exidia glandulosa does have a visually similar counterpart, Exidia nigricans, which is known as warlock's butter. The two species were thought to be the same fungus until 1966. Exidia nigricans can be distinguished by its brain-like folds and its preference for beech, ash and hazel over oak.
References
Elkhateeb, W., Daba, G., Elnahas, M. & Thomas, P. (2019). Anticoagulant Capacities of Some Medicinal Mushrooms. Journal of Pharmaceutical Sciences. 5. 12-16.
Jędrejko, K. J., Lazur, J., & Muszyńska, B. (2021). Cordyceps militaris: An Overview of Its Chemical Constituents in Relation to Biological Activity. Foods (Basel, Switzerland), 10(11), 2634.
Ke, H. M., Lee, H. H., Lin, C. I., Liu, Y. C., Lu, M. R., Hsieh, J. A., Chang, C. C., Wu, P. H., Lu, M. J., Li, J. Y., Shang, G., Lu, R. J., Nagy, L. G., Chen, P. Y., Kao, H. W., & Tsai, I. J. (2020). Mycena genomes resolve the evolution of fungal bioluminescence. Proceedings of the National Academy of Sciences of the United States of America, 117(49), 31267–31277.
Always make sure you are 100% sure of your identification before consuming any plant or mushroom