Calvatia gigantea

Most giant puffballs grow to be 10 to 50 centimetres (4 to 20 inches), sometimes to be 90 cm (35 in) in diameter; although occasionally some can reach diameters up to 150 cm (60 in) and weights of 20 kg (44 lb). The inside of mature Giant puffballs is greenish brown, whereas the interior of immature puffballs is white. The large white mushrooms are edible when young.[2][3]

The fruiting body of a puffball mushroom will develop within the period of a few weeks and soon begin to decompose and rot, at which point it is dangerous to eat. Unlike most mushrooms, all the spores of the giant puffball are created inside the fruiting body; large specimens can easily contain several trillion spores. Spores are yellowish, smooth, and 3–5 μm in size.[2][3]

The classification of this species has been revised in recent years, as the formerly recognized class Gasteromycetes, which included all puffballs, has been found to be polyphyletic. Some authors place the giant puffball and other members of genus Calvatia in order Agaricales. Also, the species has in the past been placed in two other genera, Lycoperdon and Langermannia. However, the current view is that the Giant Puffball is Calvatia.[4]

"Widespread and fairly common, and not considered of conservation concern in the UK. However, it is protected in parts of Poland and considered rare in Lithuania and of conservation concern in Norway."[1]

Old Giant puffball.

All true puffballs are considered edible when immature, but can cause digestive upset if the spores have begun to form, as indicated by the color of the flesh being not pure white (first yellow, then brown). Immature gilled species still contained within their universal veil can be look alikes for puffballs. To distinguish puffballs from poisonous fungi, they must be cut open; edible puffballs will have a solid white interior.[5] Some similar mushrooms have the white interior (or yellowish) but also have the silhouette of a cap-type mushroom on the interior when cut open. These are young cap-type mushrooms and may be poisonous.

Puffballs are a known styptic and have long been used as wound dressing,[6] either in powdered form or as slices 3 cm thick. The fungus was often harvested prior to battles for this purpose.[7]

It is the main source of the anti-tumor mucoprotein calvacin, which is present only in tiny quantities.

Giant puffballs resemble the earthball (Scleroderma citrinum). The latter are distinguished by a much firmer, elastic fruiting body, and having an interior that becomes dark purplish-black with white reticulation early in development. Scleroderma citrinum is poisonous and may cause mild intoxication.

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  Giant puffball.
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  Puffball mushrooms on sale at a market in England, showing slices uniform and white all the way through.
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  Cut, with a fork for scale.
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  Giant puffballs growing in a deciduous forest

• Zhu, Wenyou; Guo, Chunxia; Luo, Fan (January 2015). "Optimization of Calvatia gigantea myceliaproduction from distillery wastewater". Journal of the Institute of Brewing. 121 (1): 78–86. doi:10.1002/jib.200.
• Kivrak, Ibrahim; Kivrak, Seyda; Harmandar, Mansur (1 September 2014). "Free amino acid profiling in the giant puffball mushroom (Calvatia gigantea) using UPLC-MS/MS". Food Chemistry. 158: 88–92. doi:10.1016/j.foodchem.2014.02.108. PMID 24731318.
• Coetzee, Johannes C.; Van Wyk, Abraham E. (January 2013). "Nomenclatural and taxonomic notes on Calvatia (Lycoperdaceae) and associated genera". Mycotaxon. 121 (1): 29–36. doi:10.5248/121.29. hdl:2263/21213.

Wikimedia Commons has media related to Calvatia gigantea.

Wikispecies has information related to Calvatia gigantea.

• Video footage of mature Giant Puffballs
• The Giant Puffball
• VOLATILES OF THE GIANT PUFFBALL MUSHROOM (Calvatia gigantea)