Calvatia gigantea, commonly known in English as the giant puffball, is a puffball mushroom commonly found in meadows, fields, and deciduous forests in late summer and autumn. It is found in temperate areas throughout the world.
According to the Missouri Department of Conservation, Calvatia gigantea can grow 20-50 centimeters wide and 20-50 cm high.[1] First Nature explains that this fungus "can grow to 80 cm diameter and weigh several kilograms."[2] A specimen weighing over 23 kilograms was recorded on Robinson-Superior Treaty Territory in what is currently known as Thunder Bay, Ontario, Canada.[3]
The inside of a mature giant puffball (which is inedible) is greenish brown. The interior of an immature puffball (which is edible) is white.[4] [5] The Lovesick Native Women's Association explains that an overripe puffball "will fall apart when touched or if cut open" and should be discarded.[6]
Indeed, the fruiting body of a puffball mushroom develops within a few weeks and soon begins 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.
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.
The classification of this species has been revised in recent years. First Nature explains that "puffballs, earthballs, earthstars, stinkhorns and several other kinds of fungi were once thought to be related and were known as the gasteromycetes or 'stomach' fungi, because the fertile material develops inside spherical or pear-shaped fruitbodies." However, many mycologists now believe that "the gasteromycetes" do not share single ancestor; they are polyphyletic.[7]
Today, some authors place the giant puffball and other members of genus Calvatia in order Agaricales. The giant puffball has also been placed in two other genera, Lycoperdon and Langermannia, in years past. The current view is that the giant puffball is Calvatia.[8]
The giant puffball is widespread and common in the UK. It is protected in parts of Poland and is of conservation concern in Norway.
The large white mushrooms are edible when young,[4] [5] as are all true puffballs, but they can cause digestive issues if the spores have begun to form—as indicated by the color of the flesh being yellowish or greenish-brown instead of pure white.
Immature gilled species still contained within their universal veil can be lookalikes for puffballs. To distinguish puffballs from such poisonous fungi, they must be cut open; edible puffballs will have a solid white interior and have "no gills or other imperfections".[9] [10]
Puffballs are a known styptic and have long been used as wound dressing, either in powdered form or as slices 3 cm thick.[11] Authors Hui-Yeng Y. Yap, Mohammad Farhan Ariffeen Rosli, et al. found evidence to suggest Calvatia gigantea was "traditionally used by American Indians, Nigerian and German folks" for this purpose. The authors, however, did not specify the preferred form of wound dressing (e.g., powdered or sliced). [12]
New Zealand Māori used it to stem bleeding and treat burns, it was also a food source.[13]