Geastrum saccatum Fries
Syst. Myc. 3: 16. 1829.

Common Name: Earthstar

• Sporocarp

  Fruiting body puffball-shaped at first, 1-2.5 cm wide, the peridium splitting into 5 to 8 rays yielding a final diameter of approximately 5 cm.; rays, thick, fleshy, upper surface pinkish-tan to yellow-brown, recurving from the base; spore sac sessile, 0.5-2.0 cm broad, round, smooth, brown rupturing via an apical pore, the latter surrounded by a small but well-defined slightly depressed disc.

• Spores

  Spores 3.5-4.5 µm, nearly round, warted. Spores dark-brown in mass.

• Habitat

  Solitary to scattered from late fall to early spring in mixed hardwood & coniferous forests.

• Edibility

  Inedible, at least when mature.

• Comments

  Geastrum saccatum is distinguished from the several species of earthstars that occur in the S.F. Bay area by its sessile spore sac which has a small depressed disc surrounding the apical pore, and recurved non-hygroscopic rays. Geastrum triplex is similar but the spore sac sits in a shallow cup formed from splitting of peridial wall tissue; Geastrum fimbriatum also has a sessile spore sac, but the apical pore is not surrounded by a well defined depressed disc; Geastrum fornicatum has a spore sac with a short stalk and stands erect from the substrate on the tips of its rays, while Astraeus hygrometricus and A. peteridis are told apart by their hygroscopic rays.

• References

  Calonge, Francisco D. (1998). Flora Mycologica Iberica. Vol. 3. Gasteromycetes, I. Lycoperdales, Nidulariales, Phallales, Sclerodermatales, Tulostomatales. J. Cramer: Berlin, Germany. 271 p.
  Smith, A.H. (1951). Puffballs and Their Allies in Michigan. University of Michigan Press: Ann Arbor, MI. 131 p.
  Sunhede, Stellan (1989). Geastraceae (Basidiomycota) -- Morphology, Ecology, and Systematics with Special Emphasis on Northern European Species. Fungiflora: Oslo, Norway. 535 p.

• Other Descriptions and Photos
  • Taylor F. Lockwood: Geastrum saccatum (CP) -- immature sporocarp, before the outer peridium begins to split into rays
  • Taylor F. Lockwood: Geastrum saccatum (CP) -- sporocarp just beginning to open
  • Taylor F. Lockwood: Geastrum saccatum (CP) -- open sporocarp
  • Taylor F. Lockwood: Geastrum saccatum (CP) -- older specimen with rays lifting sporocarp from substrate; note sessile spore sac
  • Michael Wood: Geastrum saccatum (CP)
  • Boleslaw Kuznik -- Hunting for Mushrooms: Geastrum saccatum (CP)
  • George Barron's Fungi of Canada (East): Geastrum saccatum (D & CP)
  • Eileen's Mushroom Mania: Geastrum saccatum (CP)
  • Mushroom Observer: Geastrum saccatum (CP)
  • Arora (1986): p. 703 (D), p. 704 (P)
  • Lincoff: p. 818 (D), plate 636 (CP)
  • McKenny et al.: p. 193 (D & CP)
  • Miller: sp. 350 (D & CP)
  • Phillips: p. 286 (D & CP)
  
  

  (D=Description; I=Illustration; P=Photo; CP=Color Photo)