Lycoperdon pyriforme — Pear-shaped puffball

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Pear-shaped puffball2, photograph by Ludovic Le Renard.

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Pear-shaped puffballs7, turning brown as spores mature, photograph by Ludovic Le Renard.

Warning: although puffballs are edible, rule out poisonous look-alikes before eating any! Cut puffballs in half from top to bottom and look closely at the cut surface. The outer rind should be as thin as an eggshell; if thicker, the fungus may be a poisonous earthball (Scleroderma sp.). The interior should be white and completely uniform. If a small mushroom shape is folded inside, the specimen may be the 'egg' stage of a deadly or dangerous species such as the death cap, Amanita phalloides. If the inside is yellow or brown, the specimen is too old and bitter to eat.


Odour: None or faintly mushroomy.
Taste: Mild if the inside is uniformly white, becoming bitter when the flesh yellows.
General form: 2–6 cm tall, 1–3.5 cm broad with a non-sporulating, stem-like base supporting an enlarged, rounded or ellipsoid sporulating upper portion. Puffballs, like marshmallows, are slightly soft and squishy. White thread-like strands of mycelium often radiate from the base.
Outer layer, peridium: Surface is whitish when young, becoming tan or brown, covered with scattered spines or small granules.
Inner tissue, gleba: White and homogenous before spores start to mature. Then yellowish to yellowish-olive, and finally as internal tissues break down, drying so that only a smoky, powdery, olive-brown to brown-coloured mass of spores remains.
Sterile base: Variable in shape and size, from small and inconspicuous to wider than sporulating gleba. Interior flesh of base whitish.
Spores: 2.5–3.5 x 2.5–4 µm smooth, globose to subglobose, olive-coloured.
Spore release: A pore forms at the top of the peridium as spores mature and turn dry and dusty. Touch the side of the peridium and spores 'smoke' out of the pore. Watch a video (different kind of puffball, same mechanism).
Habitat: Growing, often in troops, on stumps, rotting logs and woodchips.
Geographical range: Widely distributed, known from North America, Europe and eastern Asia1,6.

Poisonous look alikes include the death cap (Amanita phalloides) mushroom, which starts out as a round egg that looks like puffball. Earthballs (Scleroderma species) also look like puffballs from the outside but have a thicker peridium and the internal gleba soon turns purplish black. In earthballs, the outer skin breaks open to release the spores, whereas in Lycoperdon the spores escape through a designated hole. Other Lycoperdon species are similar. Lycoperdon perlatum, the gem-studded puffball, usually grows from soil, often in disturbed areas such as woods along roadsides. Its outer surface is whitish with small, conical warts that fall off with age, leaving circular depressions and its sterile base turns brownish with age.

For most people, puffballs are edible as long as they are uniformly white inside. However, death and serious illness have resulted from eating egg stages of a death cap (Amanita phalloides) or earthball (Scleroderma species) after mistaking these for puffballs8. Slice each puffball in half to make sure it is uniform and white inside. As for other mushrooms, a few individuals have allergy-like reactions to eating puffballs8. Dogs can suffer much more than humans from inhaling puffball spores9-11.

Treatment: Contact your regional Poison Control Centre if you realize you or someone you know has become ill after eating puffballs or other mushrooms. Poison centres provide free, expert medical advice 24 hours a day, seven days a week. If possible, save the mushrooms or some of the leftover food containing the mushrooms to help confirm identification.

Poison Control:
British Columbia: 604-682-5050 or 1-800-567-8911.
United States (WA, OR, ID): 1-800-222-1222.

1
MyCoPortal. Mycology Collections Portal, accessed July 2018.

2
Specimen Lycoperdon pyriforme UBC F28388, GenBank #KP454020.

3
Siegel, N. & Schwarz, C. Mushrooms of the Redwood Coast. A Comprehensive Guide to the Fungi of Coastal Northern California. Ten Speed Press, Berkeley, California (2016).

4
Ramsey, R. Trial field key to the species of Sclerodermataceae in the Pacific Northwest. http://www.svims.ca/council/Sclero.htm (2003).

5
Arora, D. Mushrooms Demystified. Ten Speed Press, Berkeley, California (1986).

6
Kõljalg, U. et al. Towards a unified paradigm for sequence-based identification of fungi. Mol. Ecol. 22, 5271-5277, doi:10.1111/mec.12481 (2013).

7
Specimen Lycoperdon pyriforme UBC F28394, GenBank #KP454030.

8
Beug, M. W., Shaw, M. & Cochran, K. W. Thirty-plus years of mushroom poisoning: Summary of the approximately 2,000 reports in the NAMA case registry. McIlvainea 16, 47-68 (2006).

9
Rubensohn, M. Inhalation pneumonitis in a dog from spores of puffball mushrooms. Can. Vet. J. 50, 93 (2009).

10
Alenghat, T. et al. Lycoperdonosis in two dogs. J. Vet. Diagn. Invest. 22, 1002-1005, doi:10.1177/104063871002200629 (2010).

11
Buckeridge, D., Torrance, A. & Daly, M. Puffball mushroom toxicosis (lycoperdonosis) in a two-year-old dachshund. Vet. Rec. 168, 304b, doi:10.1136/vr.c6353 (2011).