page_title: Geastrum fornicatum
section_title: Description
hierarchical_section_title: Geastrum fornicatum / Description
caption_attribution_description: English: Geastrum fornicatum found under an oak tree in Crescenta Valley Community Regional Park, La Crescenta, Los Angeles Co., California, USA
context_page_description: Geastrum fornicatum, commonly known as the acrobatic earthstar or the arched earthstar, is an inedible species of mushroom in the family Geastraceae. Like other earthstar mushrooms, the thick outer skin splits open at maturity to expose the spore sac to the elements; the specific epithet fornicatum refers to the arched shape of the rays which extend downwards to rest on the mycelial sac and elevate the spore sac.
context_section_description: The immature fruit body is roughly spherical in shape, typically 1.5–2.5 cm (0.6–1.0 in) in diameter, and dark brown in color. At maturity, the exoperidium (outer layer) splits into four to five rays which curve backwards so as to elevate the fruit body and raise the spore sac for optimal spore dispersal; the tips of the rays remain attached to a basal cup. The spore sac contains an ostiole, a small opening near the apex. The mature fruiting body may be up to 6 cm (2.4 in) in diameter and 8 cm (3.1 in) tall. The exoperidium is attached to the soil by rhizomorphs. Spores are spherical, warted, thick-walled, nonamyloid and 5–6 μm. In mass, the spores have a dark-brown color.
  This species is found singly or in small groups under bushes and in deciduous woods. It is inedible.
caption: Arched earthstar found growing under an oak in southern California
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