Clathrus columnatus, commonly known as the columned stinkhorn, is member of the stinkhorn family of mushrooms. It emanates from a medium-sized white, spore case (receptacle), and consists of 2 to 5 orange to red, thick, spongy columns that unite at the apex. And, as its common name suggests, it really does have quite a fetid odor. [i]
This species was first described in 1811 by the French mycologist and botanist Louis Augustin Guillaume Bosc. Since that time, the taxonomy of this species has been variable being moved around from genus to genus. Over the last 2 centuries, this species has been a part of no less than 4 genera: Laternea by Christian Gottfried Daniel Nees von Esenbeck in 1858; Linderia by Gordon Herriot Cunningham in 1932; Colonnaria by Eduard Fischer in 1933; Linderiella by Cunningham in 1942. However, modern mycology considers most of these genera as obsolete and their members, like the columned stinkhorn, have been absorbed into the genus Clathrus.
The etymology of this specie’s name is straightforward. The generic name Clathrus means “cage-like” referring to the chamber-like cavity created by the columns. While the epithet columnatus means “supported by pillars”.
The various synonyms readers may encounter this species include Laternea columnata, Linderia columnata, Colonnaria columnata, and Linderiella columnata.
Clathrus columnatus begins life as a subterranean immature fruiting body (“egg” “volva”) that is attached to the soil by long mycelial cords. From this structure emerge several “arms” or columns that grow vertically and fuse at the top. This multi- “columned” structure is termed the mature fruiting body.
Immature Fruiting Body: The immature fruiting body is represented as a partially subterranean growth called a “volva”. This “egg”-like is white, measures approximately 2 to 3 cm in height, and is half below and half above ground. The portion of the volva that is below ground is attached to the ground by white mycelial cords.
Mature Fruiting Body: The mature fruiting body emerges by splitting the peridium (outer wall) of the immature volva. The mature fruiting body measures up to 8 cm tall and 2-5cm wide. It is formed by 3-5 tout, spongy, curved column-like arms rising separately (not from a shared stem structure) from the base and fused seamlessly at the top into a flat roof.
- Arms: The column-like arms measure approximately 1 cm in thickness, are narrowed at the base, wider towards the apex, and are curved. They are hollow, spongy, and finely pocketed. They are reddish-orange and may fade to a yellowish-pink color.
- Spore mass/slime: The spore mass is olive-brown, slimy, and fetid. It covers the inner surface of the arms just below the underside of the apex/roof.
Spores: The spores of Clathrus columnatus are embedded in the fetid, olive-tinged slime that coats the underside of the apex. They measure 3.5-5.0 × 2.0-2.5 µm in size. They are elliptical and smooth. Hyaline to faintly yellow in potassium hydroxide (KOH) and Melzer’s iodine reagent.
Smell: This species, and other stinkhorns, are known for their distinctive fetid odor. However, they may not always have an odor. For example, in their immature form, very young mature form, or when they have lost their spore slime layer in old age they may not have an odor at all. Therefore, it is not always necessary for one to always encounter this foul order when foraging for members of the stinkhorn family. Why the smell? The smell of the spore slime is very important for Clathrus columnatus and other stinkhorn mushrooms. The fetid smell serves as an attractant to flies and other insects. As these insects land onto the slimy undersurface of the mushroom, the spores embedded into the sticky slime attach to their legs and are then distributed by the insects wherever they go.
Edibility: As one mycological source puts it “The odor of fully grown specimens of the order Phalloidese is so repulsive that the question as to their poisonous character when eaten by men has not often been the subject of experiment.” As such, whether this species is edible is not known with certainty. Certain sources report is as poisonous. Therefore, consumption of this species is NOT RECOMMENDED.
Habitat: C. columnatus grows scattered or gregarious on sandy soil and sometimes on lawns/gardens. Frequently found on coastal plains.
Range: The columned stinkhorn is thought to be an invasive species to North America and is most commonly found in states with warmer climates. In the US it is distributed from North Carolina or even as high up as Pennsylvania and New York to Florida in the south and to the Gulf coast in the west. Outside of North America, it can also be found in Africa, Asia, Central America, South America, and the Caribbean.
Fruiting Season: The fruiting season of this species ranges from spring through fall. In warmer climates, it may also fruit in winter.
There are several other stinkhorn species that may resemble C. columnatus.
One species that can be confused for the columned stinkhorn is the Basket Stinkhorn (C. ruber). The latter species can be differentiated by its larger, more globular, net-like receptacle.
The Stinky Squid (Pseudocolus fusiformis) may also be confused for C. columnatus. The differentiating factor between these two species lies in whether their arms are free from each other at their bases. In the case of P. fusiformis, the arms arise from a common stem that may be very short and buried in the volva. While the arms of C. columnatus are clearly separate. Additionally, unlike the white volva of C. columnatus, the volva of P. fusiformis is grayish to grayish brown. Lastly, unlike the sandy soil which is preferred by the columned stinkhorn, the Stinky Squid prefers rotting logs and chip-mulched soil.
One last species that may be confused for the columned stinkhorn is Pseudocolus schellenbergiae. This species can be differentiated by its short stalk, brown volva, and green spore slime along the inner sides of arms.
Toxicity of Clathrus columnatus[vii]
As already mentioned the consumption of the columned stinkhorn is not recommended due to its potential toxicity. Although accounts documenting human toxicity after C. columnatus consumption do not exist, there have been older mycological studies and reports demonstrating its toxicity in animals (death of several hogs in North Carolina after consumption of C. columnatus). However, the mechanism of its toxicity or the extent of the clinical picture produced is not clear. As such, the recommendation against consumption should be heeded until more information is available.
[i] McKnight, K. H., & McKnight, V. B. (1998). COLUMN STINKHORN. In A Field Guide to Mushrooms, North America (pp. 345). Houghton Mifflin.
[ii] Kuo, M. (2020, July). Clathrus columnatus. Retrieved from the MushroomExpert
[iii] D. Arora (1986) Stinkhorns In “Mushrooms Demystified: A Comprehensive Guide to the Fleshy Fungi,” Ten Speed Press, Berkeley (p.773-774.)
[iv] Phillips, E., Gillett-Kaufman, J. L., & Smith, M. E. 2018. Stinkhorn mushrooms (Agaricomycetes: Phallales: Phallaceae). University of Florida: IFAS extension.
[v] Davis, R. M., Sommer, R., & Menge, J. A. (2012). Leucoagaricus leucothites. In Field Guide to Mushrooms of western North America, University of California Press. (pp. 89-90).
[vi] Lincoff, G. (1981). Columned Stinkhorn. In National Audubon Society Field Guide to North American mushrooms (pp. 832). Knopf.
[vii] Phillips, E., Gillett-Kaufman, J. L., & Smith, M. E. 2018. Stinkhorn mushrooms (Agaricomycetes: Phallales: Phallaceae). University of Florida: IFAS extension.