page_title: Bovista pila
section_title: Description
hierarchical_section_title: Bovista pila / Description
caption_attribution_description: English: Electron micrograph of spores of the puffball fungus Bovista pila Berk. &amp; M.A. Curtis.
context_page_description: Bovista pila, commonly known as the tumbling puffball, is a species of puffball fungus in the family Agaricaceae. A temperate species, it is widely distributed in North America, where it grows on the ground on road sides, in pastures, grassy areas, and open woods. There are few well-documented occurrences of B. pila outside North America. B. pila closely resembles the European B. nigrescens, from which it can be reliably distinguished only by microscopic characteristics.
  The egg-shaped to spherical puffball of B. pila measures up to 8 cm in diameter. Its white outer skin flakes off in age to reveal a shiny, bronze-colored inner skin that encloses a spore sac. The spores are more or less spherical, with short tube-like extensions. The puffballs are initially attached to the ground by a small cord that readily breaks off, leaving the mature puffball to be blown about. Young puffballs are edible while their internal tissue is still white and firm. B. pila puffballs have been used by the Chippewa people of North America as a charm, and as an ethnoveterinary medicine for livestock farming in western Canada.
context_section_description: B. pila has an egg-shaped to roughly spherical fruit body measuring up to 8 cm (3.1 in) in diameter. The thin (0.25 millimeter) outer tissue layer (exoperidium) is white to slightly pink. Its surface texture, initially appearing as if covered with minute flakes of bran (furfuraceous), becomes marked with irregular, crooked lines (rivulose). The exoperidium flakes off in maturity to reveal a thin, inner peridium (endoperidium). The color of this shiny inner skin, splotched with darker areas, resembles the metallic colors of bronze and copper. Bovista pila puffballs are attached to the ground by a small cord (a rhizomorph) that typically breaks off when the puffball is mature. The interior flesh, or gleba, comprises spores and surrounding capillitial tissue. Initially white and firm with tiny, irregularly shaped chambers (visible with a magnifying glass), the gleba later becomes greenish and then brown and powdery as the spores mature. In age, the upper surface of the puffball cracks and tears open. The resilient texture of the inner peridium enables the puffball to maintain its ball-like shape after it has detached from the ground. As the old puffballs get blown around, spores get shaken out of the tears.
  The spores of Bovista pila are spherical, smooth (when viewed with a light microscope), and measure 3.5–4.5 μm. They have thick walls and very short pedicels. Basidia (spore-bearing cells) are club-shaped, measuring 8–10.5 by 14–18 μm. They are usually four-spored (rarely, some are three-spored), with unequal length sterigmata between 4 and 7.4 μm. The capillitia (sterile fibers interspersed among the spores) tend to form loose balls about 2 mm in diameter. The main, trunk-like branches of the capillitia are up to 15 μm in diameter, with walls that are typically 2–3 μm thick.
caption: Short pedicels are a characteristic of B. pila spores.
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