Astraeus hygrometricus

Image © Teresa Lebel Reproduced by permission

Astraeus hygrometricus (= Geastrum hygrometricum) is a puffball of the earthstar type, distinguished from other earthstars (Geastrum) by the 7-12, leathery, hygroscopic rays (which curl inwards when dry) and the inner surface of the rays pale with darker cracks. Probably an exotic. RARE. Common Name: Barometer earthstar

• Fruiting body
  20-35 mm diam. when closed, subglobose or flattened at apex, dull greyish white to pale brown, becoming smooth. Expanded fruit-body 50-90 mm across, the outer layer splitting more than halfway into 7-13 rays, strongly hygroscopic (rays arched downwards when damp, turned upwards to cover inner spore sac when dry). Outermost layer fleshy, thick, pale buff becoming dark brown with inner overlying yellowish brown to off white layer splitting into net-like pattern.

• Hymenium
  Spore sac lacking a stem, subglobose, 15-30mm diam., pale buff; lacking a distinct pore, instead with an irregular, often longitudinal, apical tear, greyish.

• Stipe/stem
  Absent.

• Volva
  

• Ring
  

• Smell
  Not distinctive.

• Spores
  Spore print brown.

• Habitat
  On nutrient poor, usually sandy soil; forming mycorrhizal associations with various trees.

• References
  Pegler et al. 1997 British Puffballs, Earthstars and Stinkhorns

Distribution map

Last modified on 26 June 2002

Maintained by Gudrun Arnold

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