''Geastrum fimbriatum'', commonly known as the fringed earthstar or the sessile earthstar, is an inedible species of

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is t ...

belonging to the genus ''

Geastrum ''Geastrum'' (orthographical variant ''Geaster'') is a genus of puffball-like mushrooms in the family Geastraceae. Many species are known commonly as earthstars. The name, which comes from ''geo'' meaning ''earth'' and meaning ''star'', refers ...

'', or earthstar fungi. First described in 1829, the species has a widespread distribution, and is found in Asia, Europe, and the Americas. It is distinguished from other earthstars by the delicate fibers that line the circular pore at the top of its spore sac.

Taxonomy

Elias Magnus Fries Elias Magnus Fries (15 August 1794 – 8 February 1878) was a Swedish mycologist and botanist. Career Fries was born at Femsjö (Hylte Municipality), Småland, the son of the pastor there. He attended school in Växjö. He acquired ...

described ''Geastrum fimbriatum'' (as ''Geaster fimbriatus'') in his 1829 ''Systema mycologicum''. It is commonly known as the fringed earthstar or the sessile earthstar. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''fimbriatum'' means "fringed", referring to the characteristic edge of the apical spore of the spore sac.

Description

The fruit bodies of ''Geastrum fimbriatum'' start out roughly spherical and

hypogeous Hypogeal, hypogean, hypogeic and hypogeous (; ) are biological terms describing an organism's activity below the soil surface. In botany, a seed is described as showing hypogeal germination when the cotyledons of the germinating seed remain non ...

. As it matures, it pushed up through the soil and the other layer of the spore case (exo

peridium The peridium is the protective layer that encloses a mass of spores in fungi. This outer covering is a distinctive feature of gasteroid fungi. Description Depending on the species, the peridium may vary from being paper-thin to thick and rubber ...

) splits open to form between 5 and 8 rays that curve downward. The fully expanded fruit body has a diameter of up to . Before expansion, the outer surface has a cottony surface with adherent soil particles; this ultimately peels off to reveal a smooth, grayish-brown surface. The inner spore sac is yellowish brown and features a small conical pore with fringed edges. Unlike other similar earthstar fungi, the edges of this pore are not sharply delimited from the rest of the spore sac, and do not have grooves. The fruit bodies have no distinctive taste or odor. The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s are spherical, roughened by many small points or warts, and measure 2.4–4 μm. The

capillitium Capillitium (pl. capillitia) is a mass of sterile fibers within a fruit body interspersed among spores. It is found in Mycetozoa (slime molds) and gasteroid fungi of the fungal subdivision Agaricomycotina The subdivision Agaricomycotina, also kn ...

is thick-walled, unbranched, and 4–7 μm thick. Similar species include ''

Geastrum saccatum ''Geastrum saccatum'', commonly known as the rounded earthstar, is a species of mushroom belonging to the genus '' Geastrum''. It has a worldwide distribution and is found growing on rotting wood. It is considered inedible by mushroomers becaus ...

'', which is larger – up to across – and has a clearly delimited ring-like area around the pore opening. '' Geastrum rufescens'' has reddish tones that are absent from ''G. fimbriatum''. Although typically listed by field guides as an inedible species, it is eaten by the tribal peoples of

Madhya Pradesh Madhya Pradesh (, ; meaning 'central province') is a state in central India. Its capital is Bhopal, and the largest city is Indore, with Jabalpur, Ujjain, Gwalior, Sagar, and Rewa being the other major cities. Madhya Pradesh is the seco ...

Habitat and distribution

''Geastrum fimbriatum'' is a

saprobic Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ( ...

species, and it fruit bodies grow on the ground in groups or clusters, usually near the stumps of

hardwood Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from ...

trees. It is found in Asia (India l, Mongolia), eastern North America (including Mexico), Central America (Costa Rica), South America (Brazil), and Europe. The species was depicted in a Nigerian postage stamp in 1985.

References

{{Taxonbar, from=Q2484512 fimbriatum Fungi described in 1829 Inedible fungi Fungi of Europe Fungi of North America Taxa named by Elias Magnus Fries