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Danny’s DNA Discoveries – Geastrales of the PNW
by Danny Miller

Click here for my Pictorial Key to the Earth Stars


Geastrum (earth stars) - are like puffballs with thick skins, but the outer layer opens and peels back to form star-like rays. The other earth stars not covered here are the hygroscopic ones (that can close and re-open) in the Boletales. This genus contains some false truffles with a columella, which do not open in rays and grow at least partially underground. Radiigera is a newer synonym of the false truffles in this genus.

Sphaerobolus (cannon fungi) - small fruitbodies a few mm across growing on wood, they probably most resembles the Nidulariaceae (bird's nests) but these species are round, containing one big "egg" inside that is shot out like a cannonball. The outer layer peels back to form star-like rays just like Geastrum before the cannonball is shot out.

Schenella (false truffles) - these false truffles are very much like those in Geastrum, having a very thick rind, stubby interior columella, and a radial pattern inside the gleba. The outer layer has lost its ability to peel away in star-like rays, and they grow at least partially underground. Differentiating them from those false truffles inside Geastrum can be difficult. Pyrenogaster is a newer synonym.

Astraeus earth stars are in the Boletales. The hole that forms in the centre of the sphere to release the spores is an irregularly shaped slit instead of being round or poorly defined and the area around the hole is never striate nor beaked. The rays are always hygroscopic (opening in wet weather and closing again in dry weather) whereas only some Geastrum are hygroscopic. Some Astraeus have a conspicuous checkered pattern on the inside of the rays.

abundant  common  uncommon  rare - colour codes match my Pictorial Key and are my opinions and probably reflect my bias of living in W WA. Rare species may be locally common in certain places at certain times.

Summary of Interesting Results


Geastrum (earth stars) - click to expand

Species mentioned: Geastrum campestre, corollinum, coronatum, fimbriatum, floriforme, limbatum, minimum, pectinatum, quadrifidum, rufescens, saccatum, schmidelii, striatum, triplex, umbilicatum, bushnellii, fuscogleba, taylorii.

Sphaerobolus (cannon fungi) - click to expand

Species mentioned: Sphaerobolus stellatus, iowensis

Schenella (false truffles) - click to expand

Species mentioned: Schenella pityophilus, simplex.


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