| Calvatia sculpta | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Agaricomycetes |
| Order: | Agaricales |
| Family: | Agaricaceae |
| Genus: | Calvatia |
| Species: | C. sculpta |
| Binomial name | |
| Calvatia sculpta | |
| Synonyms[1] | |
| |
Calvatia sculpta | |
|---|---|
 | Glebalhymenium |
 | No distinctcap |
 | Hymenium attachment is not applicable |
| Lacks astipe |
 | Spore print isbrown |
 | Ecology ismycorrhizal |
  | Edibility isedible orinedible |
Calvatia sculpta, commonly known as thesculpted puffball, thesculptured puffball, thepyramid puffball, orSierran puffball, is a species ofpuffball fungus in the familyAgaricaceae.
Attaining dimensions of up to 8 to 15 cm (3 to 6 in) tall by 8 to 10 cm (3 to 4 in) wide, the pear- or egg-shaped puffball is readily recognizable because of the large pyramidal or polygonal warts covering its surface. Thespores are roughly spherical and have wart-like projections on their surfaces. It may be easily confused withCalbovista subsculpta, a similar puffball that—in addition to differences observable only with amicroscope—is larger, and has slightly raised warts with a felt-like texture. Other similar species includeCalvatia arctica and immature specimens ofAmanita magniverrucata.
Originally described from theSierra Nevada,C. sculpta is found in mountainous areas in western North America, and was found in a Brazilian dune in 2008. It isedible when young, before the spores inside thefruit body disintegrate into a brownish powder.
The species was first described in 1885 by American mycologistHarvey Willson Harkness, under the nameLycoperdon sculptum. Harkness, who called it "a curious and strikingly beautiful species", found fruit bodies growing at elevations between 6,000 and 8,000 feet (1,800 and 2,400 m) in theSierra Nevada mountains. Although he noted that "in appearance it differs so much from any species known to us, as to be almost deemed worthy of generic rank", he thought that placement in the puffball genusLycoperdon was the most appropriateclassification, despite its unusualcortex.[2] Harkness's type collections were destroyed in the fires following the1906 San Francisco earthquake.[3] In 1904,Curtis Gates Lloyd considered the species better placed inCalvatia, because of the resemblance of its deeply colored capillitial threads (coarse thick-walled cells found in thegleba) to those ofCalvatia caelata;[nb 1] he called the speciesCalvatia sculptum.[7] The mushroom is known by severalcommon names, including the "sculpted puffball", the "sculptured puffball", the "pyramid puffball",[8] and the "Sierran puffball".[9]
In 1992, German mycologistHanns Kreisel, in his survey of the genusCalvatia, defined thesectionSculpta to containC. sculpta andC. subcretacea.[10] Two years later he merged the sectionCretacea intoSculpta[11] when it was shown thatC. subcretacea wassynonymous with the arctic-alpine speciesC. arctica.[12]
The white pear- or egg-shapedfruit body ofC. sculpta may be 8 to 15 cm (3 to 6 in) tall by 8 to 10 cm (3 to 4 in) wide. The outer layer of tissue, known as the exoperidium, is covered on the outer surface with distinctive long, pointed, pyramid-shaped warts, either erect or bent over and sometimes connected at the tip with other warts.[13] The warts bear parallel horizontal lines towards the base. MycologistDavid Arora opined thatC. sculpta resembles "a cross between a geodesic dome and a giant glob of meringue".[9] In age, theperidium sloughs off and exposes a brownishspore mass. The interior of the puffball, thegleba, is firm and yellowish-white when young, but gradually becomes powdery and deep olive-brown as it matures.[13]
Thespores are roughly spherical, thick-walled, 3–6 μm in diameter (although some specimens collected in the US range from 7.2 to 9.5 μm),[14] and are covered with minute spines or warts.[15] The use ofscanning electron microscopy has revealed that these ornamentations on the spores are typically 0.95 μm long. Sporeultrastructure is distinctive amongCalvatia species, and has been used to help verify taxonomic groupings and confirm the status of species within the genus.[16] The capillitia (coarse, thick-walledhyphae in the gleba) areseptate, with branches that are narrowed towards the tips; they are 3–8 μm in diameter.[15] When grown inpure culture in the laboratory,C. sculpta is, under certain conditions, able to grow structures calledmycelial strands. These are linear aggregates of hyphae whereby older "leading" hyphae become enclosed by coiled layers of newer "tendril" hyphae. Mycelial strands provide a conduit for transporting water and nutrients across non-nutrient material, allowing the fungus to reach new sources of food.[17] They are also implicated in the formation of fruit bodies andsclerotia. The mycelia ofC. sculpta can be induced to form mycelial strands when there is a permeable physical barrier between it and theagar substrate.[18] The wide hyphae in the center of the mycelial strands contain protein-dense structures on their cell walls that are shaped like atorus. Their function is unknown.[19]
Calvatia sculpta isedible and said to be "choice" by some authors.[9][13] The taste is described as "mild" and the flesh has no distinguishable odor.[13] Arora recommends eating the puffball only when it is firm and white inside, as older specimens may have a distastefuliodine-like flavor.[20] The puffball may be preserved by freezing fresh or partially cooked slices, but their flavor and texture will deteriorate unless cooked immediately after thawing. Recommended cooking techniques for puffball slices includesautéing and coating inbatter before frying.[8]C. sculpta was used as a traditional food of thePlains and Sierra Miwok Indians of North America, who called the funguspotokele orpatapsi.[21] Puffballs were prepared by drying them in the sun, grinding them with a mortar, and boiling them before eating with acorn soup.[22][23]
The giant western puffball,Calvatia booniana, is much larger thanC. sculpta—up to 60 cm (24 in) in diameter and 30 cm (12 in) tall—and has a smoother surface.[24] Mature specimens ofCalvatia arctica (synonymous withCalvatia subcretacea,Gastropila subcretacea, andHandkea subcretacea)[1][12] can resemble immature specimens ofC. sculpta. It is distinguished fromC. sculpta by its tough, thickerperidial wall,[15] and its scales are tipped with gray-brown.[25]Calbovista subsculpta is similar in appearance, but has more flattened and less prominent pyramidal warts. Microscopically, its capillitia are thin-walled and frequently and irregularly branched, in contrast to the thick-walled infrequently branched capillitia ofC. sculpta.[13] The "possibly toxic"Amanita magniverrucata, in itsembryonic stage, has a superficial resemblance as it also has pyramidal cap warts. However, it grows at different elevations and different seasons thanC. sculpta. Further, slicing the fruit body ofA. magniverrucata in half will reveal internal structures ofcap,gills andstem not present in puffballs.[26]
The sculptured puffball grows solitarily or in small groups inforest duff. It is typically associated withconiferous forests at high elevations, greater than about 750 m (2,500 ft),[27] on western mountains like the Sierra Nevada and theCascade Range.[15][20] The United States distribution includes the states ofCalifornia,Oregon,Washington, andIdaho.[28] An uncommon species,[9] it fruits throughout spring, summer, and fall during wet weather.[13]
Most commonly known from western North America,[13] the species was reported growing on sandy soil inNatal Dunes State Park in thenortheastern Brazilian state ofRio Grande do Norte in 2008. The fruit bodies were associated with the roots of the native tree speciesEugenia brasiliensis. Several hypotheses have been proposed to account for thisdisjunct distribution: the species may have been present before the Americas separated; it may have beenintroduced to Brazil by human activity, and subsequently adapted to the environment there; or the North and South American populations may represent acryptic species complex—appearingmorphologically similar but genetically distinct. The Brazilian population has not been compared genetically with North American specimens.[14]
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