|Major Groups > Puffballs > Calvatia fragilis|
by Michael Kuo
Calvatia fragilis is essentially a smaller version of the well-known Calvatia cyathiformis. Like that species, it has purple-brown spore dust at maturity and, under the microscope, it features spiny spores. Calvatia fragilis differs, however, in its smaller size and in the fact that it lacks a substantial sterile base section.
Some mycologists treat Calvatia fragilis as a mere form of Calvatia cyathiformis (officially, "Calvatia cyathiformis f.
Ecology: Saprobic; terrestrial; growing alone, gregariously, or in fairy rings in grass—on lawns, in meadows, and so on; summer and early fall; widely distributed in North America. The illustrated and described collections are from Illinois and Québec.
Fruiting Body: Shaped like a ball, or nearly so; 2–8 cm across and 2–4 cm high; whitish to gray or pale grayish brown, or purplish in places; with age the surface usually developing a mosaic pattern; outer "skin" about 1 mm thick; interior flesh white, becoming yellow to yellowish and eventually turning into purple-brown spore dust; basal area lacking or extremely rudimentary (and then composed of cottony fibers).
Odor and Taste: Not distinctive.
Chemical Reactions: KOH negative on surface.
Microscopic Features: Spores 4–5.5 µm (measured without ornamentation); globose or subglobose; densely spiny with spines 1–1.5 µm long; hyaline in KOH. Capillitial threads 2–10 µm wide; thick-walled; septate; hyaline in KOH.
REFERENCES: (Quélet, 1886) Morgan, 1890. (Saccardo, 1888; Coker & Couch, 1928; Smith, 1951; Zeller & Smith, 1964; Smith, Smith & Weber, 1981; Kreisel, 1994; Desjardin, Wood & Stevens, 2015; Seigel & Schwarz, 2016.) Herb. Kuo 10310701, 07120803.
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Cite this page as:
Kuo, M. (2017, September). Calvatia fragilis. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/calvatia_fragilis.html