About this fungus
Collared Earthstar is a fungus in the Geastraceae family. Its habitat and field characteristics are summarised below.
A large earthstar with thick rays whose inner layer commonly splits to form a saucer-like collar beneath the central spore sac.
What to check
Look for the separate collar, a relatively large sessile spore sac and a fibrous mouth surrounded by a paler defined zone. There are no gills, ring or volva. The collar is important but may be incomplete or absent in some fruit bodies.
Variation
Fresh rays are cream to pinkish-buff and mature grey-brown. The collar develops as the thick inner layer cracks, so young, damaged or unusually formed specimens may lack the textbook shape.
Lookalikes
Rounded Earthstar is smaller and lacks a true separated collar, although old names and older literature have confused the two. Several large earthstars overlap and may require mouth, sac-surface and spore characters.
Habitat and range
Saprotrophic in rich humus and deep leaf litter under broadleaved trees and conifers, often on slopes or disturbed woodland soil. It is widespread but the triplex name may cover more than one genetic lineage.
Food safety
Inedible.
Photographs
Amadej Trnkoczy / CC BY-SA 3.0