Phallus impudicus

Common Stinkhorn Scientific classification Kingdom: Fungi Division: Basidiomycota Class: Agaricomycetes Order: Phallales Family: Phallaceae Genus: Phallus Species: P. impudicus Binomial name Phallus impudicus L. (1753) Synonyms[1] Phallus volvatus Batsch (1783) Phallus foetidus Sowerby (1803) Morellus impudicus (Pers.) Eaton (1818) Ithyphallus impudicus (L.) E.Fischer (1888) Phallus impudicus Mycological characteristics glebal hymenium cap is conical stipe is bare ecology is saprotrophic edibility: edible or inedible

Phallus impudicus, known colloquially as the common stinkhorn, is a widespread fungus recognizable for its foul odor and its phallic shape when mature, the latter feature giving rise to several names in 17th-century England. It is a common mushroom in Europe and western North America, where it occurs in habitats rich in wood debris such as forests and mulched gardens. It appears from summer to late autumn. The fruiting structure is tall and white with a slimy, dark olive colored conical head. Known as the gleba, this material contains the spores, and is transported by insects which are attracted by the odor – described as resembling carrion. Despite its foul smell, it is not poisonous and the young mushroom is consumed in parts of France and Germany.

Taxonomy

Botanist John Gerard called it the "pricke mushroom" or "fungus virilis penis effigie" in his General Historie of Plants of 1597, and John Parkinson referred to it as "Hollanders workingtoole" or "phallus hollandicus" in his Theatrum botanicum of 1640.^[2] Linnaeus was responsible for the fairly obvious genus name.^[3] Its specific epithet, impudicus, is derived from the Latin for "shameless" or "immodest".^[4]

Description

Sometimes called the witch's egg,^[5] the immature stinkhorn is whitish or pinkish, egg-shaped, and typically 4 to 6 cm (1.6 to 2.4 in) by 3 to 5 cm (1.2 to 2.0 in).^[6]

An immature fruiting body ("egg") in longitudinal section

On the outside is a thick whitish volva, also known as the peridium, covering the olive-colored gelatinous gleba. It is the latter that contains the spores and later stinks and attracts the flies; within this layer is a green layer which will become the 'head' of the expanded fruit body; and inside this is a white structure called the receptaculum (the stalk when expanded), that is hard, but has an airy structure like a sponge.^[7] The eggs become fully grown stinkhorns very rapidly, over a day or two.^[5] The mature stinkhorn is 10 to 25 cm (3.9 to 9.8 in) tall and 4 to 5 cm (1.6 to 2.0 in) in diameter,^[6] topped with a conical cap 2 to 4 cm (0.8 to 1.6 in) high that is covered with a greenish-brown slime termed the gleba. In older fungi the slime is eventually removed, exposing a bare yellowish pitted and ridged (reticulate) surface. This has a passing resemblance to the common morel (Morchella esculenta), with which it is sometimes mistaken.^[8] The rate of growth of Phallus impudicus has been measured at 10–15 cm (3.9–5.9 in) per hour. The growing fruit body is able to exert up to 1.33 kN/m² of pressure—a force sufficient to push up through asphalt.^[9]

The spores have an elliptical to oblong shape, with dimensions of 3–5 to 1.5–2.5 µm.^[8]

Spore dispersal

The dispersal of spores is different from most "typical" mushrooms that spread their spores through the air. Stinkhorns instead produce a sticky spore mass on their tip which has a sharp, sickly-sweet odor of carrion to attract flies and other insects. Odorous chemicals in the gleba include methanethiol, hydrogen sulfide,^[10] linalool, trans-ocimene, phenylacetaldehyde, dimethyl sulfide, and trimethyl sulfide.^[11] The latter compound has been found to be emitted from fungating cancerous wounds.^[12] The mature fruiting bodies can be smelled from a considerable distance in the woods, and at close quarters most people find the cloying stink extremely repulsive. The flies land in the gleba and in doing so collect the spore mass on their legs and carry it to other locations.^[13] An Austrian study demonstrated that blow-flies (species Calliphora erythrocephala, Lucilia caesar, Lucilia ampullacea and Dryomyza analis) also feed on the slime, and soon after leaving the fruit body, they deposit liquid feces that contain a dense suspension of spores.^[14] The study also showed that beetles (Oecoptoma thoracica and Meligethes viridescena) are attracted to the fungus, but seem to have less of a role in spore dispersal as they tend to feed on the hyphal tissue of the fruiting body.

There is also a possible ecological association between the P. impudicus and badger (Meles meles) setts.^[15] Fruiting bodies are commonly clustered in a zone 24 to 39 metres (79 to 128 ft) from the entrances of setts;^[16] setts also typically harbor a regularly available supply of badger cadavers—the mortality rate of cubs is high and most likely occurs within the setts.^[17] The fruiting of large numbers of stinkhorns attracts a high population of blowflies to the badger setts; the proximity to badger carcasses entices the flies to lay their eggs (Calliphora and Lucilla breed on carrion)^[18] and help ensure that they are more quickly eliminated, removing a potential source of disease. The laxative effect of the gleba reduces the distance from the fruiting body to where the spores are deposited, ensuring the continued production of high densities of stinkhorns.^[16]

Distribution and habitat

The common stinkhorn can be found throughout much of Europe and North America, and it has also been collected in Asia (including China,^[19] Taiwan,^[20] and India^[21]), Costa Rica,^[22] Iceland,^[23] Tanzania,^[24] and southeast Australia.^[25] In North America, it is most common west of the Mississippi River; Ravenel's stinkhorn (Phallus ravenelii) is more common to the east.^[26] The fungus is associated with rotting wood, and as such it is most commonly encountered in deciduous woods where it fruits from summer to late autumn, though it may also be found in conifer woods or even grassy areas such as parks and gardens.^[7] It may also form mycorrhizal associations with certain trees.^[27]

Uses

Edibility

At the egg stage, pieces of the inner layer (the receptaculum) can be cut out with a knife and eaten raw.^[28] They are crisp and crunchy with an attractive radishy taste.^[29] The fungus is enjoyed and eaten in France and parts of Germany, where it may be sold fresh or pickled and used in sausages.^[7] Similar species are consumed in China.

Medicinal properties

Venous thrombosis, the formation of a blood clot in a vein, is a common cause of death in breast cancer patients; patients with recurrent disease are typically maintained on anticoagulants for their lifetimes. A research study has suggested that extracts from P. impudicus can reduce the risk of this condition by reducing the incidence of platelet aggregation, and may have potential as a supportive preventative nutrition.^[30] It was used in medieval times as a cure for gout and as a love potion.^[7]

Folk uses

In Northern Montenegro, peasants rub Phallus impudicus on the necks of bulls before bull fighting contests in an attempt to make them stronger. They are also fed to young bulls as they are thought to be a potent aphrodisiac.^[9]

In culture

Writing about life in Victorian Cambridge, Gwen Raverat (granddaughter of Charles Darwin) describes the 'sport' of Stinkhorn hunting:

In our native woods there grows a kind of toadstool, called in the vernacular The Stinkhorn, though in Latin it bears a grosser name. The name is justified, for the fungus can be hunted by the scent alone; and this was Aunt Etty's great invention. Armed with a basket and a pointed stick, and wearing special hunting cloak and gloves, she would sniff her way round the wood, pausing here and there, her nostrils twitching, when she caught a whiff of her prey; then at last, with a deadly pounce, she would fall upon her victim, and poke his putrid carcass into her basket. At the end of the day's sport, the catch was brought back and burnt in the deepest secrecy on the drawing-room fire, with the door locked; because of the morals of the maids.^[31]

In Thomas Mann's novel The Magic Mountain (Der Zauberberg), the psychologist Dr. Krokowski gives a lecture on the phallus impudicus:

And Dr. Krokowski had spoken about one fungus, famous since classical antiquity for its form and the powers ascribed to it -- a morel, its Latin name ending in the adjective impudicus, its form reminiscent of love, and its odor, of death. For the stench given off by the impudicus was strikingly like that of a decaying corpse, the odor coming from greenish, viscous slime that carried its spores and dripped from the bell-shaped cap. And even today, among the uneducated, this morel was thought to be an aphrodisiac. ^[32]

References

1. ^ "Phallus impudicus L. 1753". MycoBank. International Mycological Association. http://www.mycobank.org/MycoTaxo.aspx?Link=T&Rec=245934. Retrieved 2011-06-17. 
2. ^ Benjamin, Denis R. (1995). "Cultural attitudes toward mushrooms". Mushrooms: Poisons and Panaceas—A Handbook for Naturalists, Mycologists and Physicians. New York, New York: WH Freeman and Company. pp. 6–7. ISBN 0-7167-2600-9. 
3. ^ Linnaeus C. (1753) (in Latin). Species Plantarum. 2. Stockholm, Sweden: Impensis Laurentii Salvii. p. 1178. http://biodiversitylibrary.org/page/359199. 
4. ^ Simpson, D.P. (1979). Cassell's Latin Dictionary (5 ed.). London, UK: Cassell Ltd. p. 883. ISBN 0-304-52257-0. 
5. ^ ^{a b} Persson, Olle; Nilsson, Sven (1978). Fungi of Northern Europe. New York, New York: Penguin Books. ISBN 0-14-063005-8. 
6. ^ ^{a b} Ellis, J. Pamela; Ellis, Martin B. (1990). Fungi without Gills (Hymenomycetes and Gasteromycetes): An Identification Handbook. London, UK: Chapman and Hall. p. 244. ISBN 0-412-36970-2. 
7. ^ ^{a b c d} Zeitlmayr, Linus (1976). Wild Mushrooms: An Illustrated Handbook. Hertfordshire, UK: Garden City Press. ISBN 0-584-10324-7. 
8. ^ ^{a b} Arora, David (1986). Mushrooms Demystified: a Comprehensive Guide to the Fleshy Fungi. Berkeley, California: Ten Speed Press. pp. 768–69. ISBN 0-89815-169-4. http://books.google.com/books?id=n3rVpkZII8IC&pg=RA1-PA768. 
9. ^ ^{a b} Niksic, M.; Hadzic, I.; Glisic, M. (2004). "Is Phallus impudicus a mycological giant?". Mycologist 18 (1): 21–22. doi:10.1017/S0269915X04001041. 
10. ^ List, P.H.; Freund, B. (1967). "Methylmercaptan und schwefelwasserstoff, geruchstoffe der stinkmorchel (Phallus impudicus L.) [Methylmercaptane and hydrogen sulfide odorous substances of stink-morel (Phallus impudicus)]" (in German). Naturwissenschaften 54 (24): 648. PMID 5590206. 
11. ^ Borg-Karlson, Anna-Karin; Englund, Finn O.; Unelius, C. Rikard (1994). "Dimethyl oligosulphides, major volatiles released from Sauromatum guttatum and Phallus impudicus". Phytochemistry 35 (2): 321–23. doi:10.1016/S0031-9422(00)94756-3. 
12. ^ Shirasu, Mika; Nagai, Shunji; Hayashi, Ryuichi; Ochiai, Atsushi; Touhara, Kazushige (2009). "Dimethyl trisulfide as a characteristic odor associated with fungating cancer wounds". Bioscience, Biotechnology, and Biochemistry 73 (9): 2117–20. doi:10.1271/bbb.90229. PMID 19734656. 
13. ^ Hall, Ian R. (2003). Edible and Poisonous Mushrooms of the World. Portland, Oregon: Timber Press. p. 250. ISBN 0-88192-586-1. http://books.google.com/books?id=yqHA_M7BVRcC&pg=PA247. 
14. ^ Schremmer, F. (1963). "Wechselbeziehungen zwischen Pilzen und Insekten. Beobachtungen an der Stinkmorchel, Phallus impudicus L. ex Pers [Interrelations between mushrooms and insects. Observations on Phallus impudicus]" (in German). Oesterreichische Botanische Zeitschrift 110 (4): 380–400. doi:10.1007/BF01373675. 
15. ^ Sleeman, D.P.; Cronin, J.N; Jones, P. (1995). "Initial observations on stinkhorn fungi at badger setts". Irish Naturalist's Journal 26: 76–77. 
16. ^ ^{a b} Sleeman, D.P.; Jones, P.; Cronin, J.N. (1996). "Investigations of an association between the stinkhorn fungus and badger setts". Journal of Natural History 31 (6): 983–92. doi:10.1080/00222939700770481. 
17. ^ Clark, M.; Neal, E.G.; Cheeseman, C.; Davies, J. (1996). Badgers. London, UK: T & AD Poyser. ISBN 0-85661-082-8. 
18. ^ Hancox, M. (1991). "The insect fauna and decomposition of badger carrion". Amateur Entomology Society Bulletin 50: 255–57. 
19. ^ Bau, Y-S; Liu B. (1984). "Phalloides of China". Life Sciences Advances 3 (1): 50–55. 
20. ^ Hosaka, K. (2010). "Preliminary list of Phallales (Phallomycetidae, Basidiomycota) in Taiwan". Memoirs of the National Museum of Nature and Science (46): 57–64. 
21. ^ Khare, B. (1976). "Some Gasteromycetes from Uttar Pradesh India". Indian Phytopahtology 29 (1): 34–38. 
22. ^ Saenz, J.A.; Nassar, M. (1982). "Mushrooms of Costa Rica – families Phallaceae and Clathraceae". Revista de Biologia Tropical 30 (1): 41–52. 
23. ^ Hallgrimsson, H.; Jensson, E.; Kristinsson, H. (1992). "Three new Gasteromycetes discovered in Iceland" (in Icelandic). Náttúrufræðingurinn 61 (3–4): 219–27. 
24. ^ Calonge, F.D.; Harkonen, M.; Saarimaki, T.; Mwasumbi, L. (1997). "Tanzanian mushrooms and their uses. 5. Some notes on the Gasteromycetes". Karstenia 37 (1): 3–10. 
25. ^ Orchard, Anthony E. (1996). Fungi of Australia. Canberra, Australia: Australian Biological Resources Study. p. 141. ISBN 0-643-06907-0. 
26. ^ Dickinson, Colin; Lucas, John (1979). The Encyclopedia of Mushrooms. London, UK: Orbis Publishing. ISBN 0856130567. 
27. ^ Andersson, O. (1989). "The distribution and ecology of Phallus impudicus in the Nordic countries". Svensk Botanisk Tidskrift 83 (4): 219–41. 
28. ^ Bon, Marcel (1987). The Mushrooms and Toadstools of Britain and North-western Europe. London, UK: Hodder & Stoughton. p. 300. ISBN 0-340-39935-X.  The entry for P. impudicus in this book explains the structure and mentions the edibility of the inner layer.
29. ^ Schaechter, Elio (1998). In the Company of Mushrooms: A Biologist's Tale. Cambridge, UK: Harvard University Press. pp. 172–73. ISBN 0-674-44555-4. http://books.google.com/books?id=DSDmd4FfuQ0C&pg=PA170. 
30. ^ Kuznecov, G.; Jegina, K.; Kuznecovs, S.; Kuznecovs, I. (2007). "Phallus impudicus in thromboprophlyaxis in breast cancer patients undergoing chemotherapy and hormonal treatment". The Breast 16 (S1): S56. 
31. ^ Raverat, Gwen (1952). Period Piece: A Cambridge childhood. London, UK: Faber. p. 136. ISBN 0-571-06742-5. 
32. ^ Thomas Mann (1995). The Magic Mountain, translated by John E. Woods. New York: Alfred A. Knopf. pp. 358–359. ISBN 0-679-44183-2.

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