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Geastrum striatum (DC.) - Striated Earthstar

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Geastrales - Family: Geastraceae

Geastrum pectinatum, Striated Earthstar fungus

The Striated Earthstar is an uncommon find, and it is very easy to miss because it blends in so well with fallen leaves and other dead vegetation under trees, which is where this earthstar generally occurs.

Distribution

From mid summer through to winter and often into the following spring the Striated Earthstar can be seen in Britain and Ireland as well as in many parts of northern and central mainland Europe including Sweden and France.

Taxonomic history

The basionym of this species dates from 1801, when the Striated Earthstar was described scientifically by Augustin Pyramis De Candolle and given the binomial scientific name Geastrum striatum by which it is generally known today.

Synonyms of Geastrum striatum include Geastrum bryantii Berk., Geastrum calyculatum Fuckel, Geastrum kunzei G. Winter and Geastrum pectinatum var. calyculatum (Fuckel) Quél.

Etymology

Geastrum, the generic name, comes from Geo- meaning earth, and -astrum meaning a star. Earthstar it is, then. The specific epithet striatum means 'striped or ribbed' (striated) and is a reference to the striations around the beak-like pore.

Identification guide

Spore sac and pore (spore exit hole) of Geastrum striatum

Spore sac

The pale greyish-blue to greyish-buff spore sac (often referred to as the bulb) is 1 to 2cm across and subglobose (in the form of a vertically compressed sphere) with a long, striated beak terminating in a small round pore via which spores emerge. There is a basal colar (evident in the main picture, see above), below which is a short stem connecting to the rayed base (the rays being formed when the outer peridium splits).

Rayed base of Geastrum striatum

Ray structure

The outer peridium, which at maturity forms the base of the fruitbody, comprises six to nine irregular pointed rays up to 6cm across when fully expanded. The spore sac is joined to its base via a short stalk that has a distinct basal collar - this feature differentiates the Striated Earthstar from the slightly larger but otherwise very similar Beaked Earthstar Geastrum pectinatum.

Spores of Geastrum striatum

Spores

Globose, warty, 4-5μm diameter excluding the warts.

Show larger image

Spore mass

Dark brown.

Odour/taste

Not noticeable.

Habitat

Mainly found on dryish soils under conifers, particularly Leylandii in Britain, but sometimes also found with hardwood trees..

Season

Fruiting in the autumn; long lasting, and often visible all year round.

Similar species

Geastrum pectinatum has no collar below its spore sac.

Culinary Notes

Earthstars are inedible and have no culinary value, but when dried they can make attractive table decorations as long as they do not get mistaken for pepper shakers!

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2016.

Pegler, D.N., Laessoe, T. & Spooner, B.M (1995). British Puffballs, Earthstars and Stinkhorns. Royal Botanic Gardens, Kew.

Ellis J B, Ellis M B. (1990). Fungi without Gills (Hymenomycetes and Gasteromycetes): an Identification Handbook. London: Chapman and Hall. ISBN 0-412-36970-2.

BMS List of English Names for Fungi

Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi and (for basidiomycetes) on Kew's Checklist of the British & Irish Basidiomycota.

Acknowledgements

This page includes pictures kindly contributed by Simon Harding.

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