Geastrum welwitschii
Encyclopedia
Geastrum welwitschii is a species of fungus
in the earthstar family
. When young and unopened, the fruit bodies
resemble small spheres lying in the soil. As the mushroom matures, the thick leathery outer layer of tissue (the peridium
) splits star-like to form a number of fleshy arms, which curve downward to reveal the inner spore sac that contains the fertile tissue known as the gleba
. The spore sac has a narrow grooved opening at the top where the spores are released. Fully expanded, the fruit bodies are up to 35 mm (1.4 in) wide and 58 mm (2.3 in) tall. First collected from Spain in the mid-19th century, the fungus is distributed in Europe, North America, and Bermuda
.
The fungus was first collected in Spain by the Austrian explorer and botanist Friedrich Welwitsch
. British mycologist Miles Joseph Berkeley
obtained the specimens and thought them to be Geastrum fimbriatum
. He sent a specimen to the French mycologist Camille Montagne
in 1856, who named it Geaster Welwitschii (Geaster is an orthographical variant of Geastrum). Patricio Ponce de León
in his 1968 world monograph
of Geastrum, considered the species a fornicate variety of G. javanicum, and described it as Geastrum javanicum var. welwitschii; this is now a synonym
.
According to Stanek's infrageneric (ranks below the level of genus
) concept of the genus Geastrum
, G. welwitschii is classified in the section Basimyceliata, which includes species in which the outer part of the mycelial layer do not incorporate sand and encrusting debris. It is further classified in the subsection Laevistomata because its peristome
(an opening at the top of the spore sac) is even to fibrillose (with fibrils).
layer does not encrust debris as the fruit body develops. The peristome is even, and has an indistinct boundary. The young fruit bodies just prior to opening are found near the surface of the ground, and are rounded, with or without an umbo
, and attached to the substrate
with a basal mycelial
tuft or cord. The expanded fruit body is small to medium-sized. The fornicate exoperidium (outer peridium
) has the upper, arched part (fibrous and pseudoparenchymatous layers) split to about the half-way point or more into 4–7 rays. The mycelial cup is free (only attached at its base), with 4–7 more or less well-developed lobes corresponding to the 4–7 rays. The width of the fruit body is about 20 –, and in height about 40 – (including the 15–20 mm high mycelial cup). The diameter of the exoperidium is about 39 –.
The pseudoparenchymatous layer (a layer of thin-walled, usually angular, randomly arranged cells that are tightly packed) is initially beige, later brownish, in age dark brown, cracked and if moist reddish-brown. The fibrous layer is beige-colored, with its outer side free from the mycelial layer except at the tips of the rays. The mycelial layer has a beige brown to somewhat yellowish-brown, felted to tufted outer surface, darkening to reddish brown if moist. It is not encrusted with debris, but some debris and sand may adhere. The inner side is smooth, dull to somewhat glossy, and hazelnut brown.
The spore sac is stalked
, and roughly spherical, with a diameter of about 8 –. The stalk is short but distinct, up to 1.5 mm (0.0590551181102362 in) high, light beige in color, and sometimes indistinctly developed. The endoperidium (inner peridium) is more or less smooth to the unaided eye, but densely protruding light to grayish-brown hypha
l tips are present. The peristome is indistinctly delimited (without distinct boundaries), and the mouth area fibrillose. The columella is not well-developed, and broadly club-shaped to columnar; in cross-section it is whitish to pale beige. The mature gleba
is brown and powdery.
The spore
s of Geastrum welwitschii are roughly spherical, sometimes contain an oil droplet, and measure 4.5–5.5 μm
in diameter. Scanning electron microscopy has revealed that the spore surface is covered with column-like processes, up to 0.45 μm high, that may be more or less confluent.
similar to G. fornicatum
in having fornicate, mostly 3–6 rays, of exoperidia and a cup-shaped mycelial layer. Geastrum welwitschii is distinguished from G. fornicatum by its epigeal mycelial cup with a felted or tufted outer surface.
Geastrum welwitschii also has similar morphological characters to G. minimum in having small fruit bodies, whitish spore sacs, and fibrillose peristomes. However G. welwitschii is differentiated from G. minimum by its fornicate, mostly 3–6, rays of the exoperidia, and the mycelial layer that easily loosens from the fibrous layer to form a mycelial cup. G. welwitschii is distinguished from G. entomophilum
by its dark and sessile endoperidium, and smaller spores (2.8–3.5 μm).
According to mycologists Hemmes and Desjardin, the most common earthstar in the coastal Casuarina
forests of Hawaii
is a species "closely allied" with G. welwitschii, which they name Geastrum aff. welwitschii. It differs from the main species in its much coarser pyramidal warts on the exoperidial surface, a sessile and sac-shaped endoperidial body, and smaller spores. They likened the roughened outer surface of the exoperidium to lychee
fruit.
, Florida
, and Bermuda
.
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
in the earthstar family
Geastraceae
The earthstars are the family Geastraceae of gasterocarpic basidiomycetes . It includes the genera Geastrum and Myriostoma. About sixty-four species are classified in this family, divided among eight genera....
. When young and unopened, the fruit bodies
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
resemble small spheres lying in the soil. As the mushroom matures, the thick leathery outer layer of tissue (the peridium
Peridium
The peridium is the protective layer that encloses a mass of spores in fungi. This outer covering is a distinctive feature of the Gasteromycetes.-Description:...
) splits star-like to form a number of fleshy arms, which curve downward to reveal the inner spore sac that contains the fertile tissue known as the gleba
Gleba
Gleba is the fleshy spore-bearing inner mass of fungi such as the puffball or stinkhorn.The gleba is a solid mass of spores, generated within an enclosed area within the sporocarp. The continuous maturity of the sporogenous cells leave the spores behind as a powdery mass that can be easily blown away...
. The spore sac has a narrow grooved opening at the top where the spores are released. Fully expanded, the fruit bodies are up to 35 mm (1.4 in) wide and 58 mm (2.3 in) tall. First collected from Spain in the mid-19th century, the fungus is distributed in Europe, North America, and Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
.
Taxonomy
Friedrich Welwitsch
Friedrich Martin Josef Welwitsch was an Austrian explorer and botanist who in Angola discovered the plant Welwitschia mirabilis...
. British mycologist Miles Joseph Berkeley
Miles Joseph Berkeley
Miles Joseph Berkeley was an English cryptogamist and clergyman, and one of the founders of the science of plant pathology....
obtained the specimens and thought them to be Geastrum fimbriatum
Geastrum fimbriatum
Geastrum fimbriatum or Rounded Earthstar is an inedible species of mushroom belonging to the genus Geastrum, or earthstar fungi.-External links:*...
. He sent a specimen to the French mycologist Camille Montagne
Camille Montagne
Jean Pierre François Camille Montagne was a French military physician and botanist who specialized in the fields of bryology and mycology. He was born in the commune of Vaudoy in the department of Seine-et-Marne....
in 1856, who named it Geaster Welwitschii (Geaster is an orthographical variant of Geastrum). Patricio Ponce de León
Patricio Ponce de León
Patricio Ponce de León was a Cuban mycologist. He was a professor at Belen School in Havana and at the University of Havana, and later a curator at the Field Museum of Natural History in Chicago, Illinois. He wrote a monograph on the worldwide species of the family Geastraceae, the earthstar fungi...
in his 1968 world monograph
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
of Geastrum, considered the species a fornicate variety of G. javanicum, and described it as Geastrum javanicum var. welwitschii; this is now a synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
.
According to Stanek's infrageneric (ranks below the level of genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
) concept of the genus Geastrum
Geastrum
Geastrum is a genus of mushroom in the family Geastraceae. Many species are known commonly as earthstars.The name comes from geo meaning earth and aster meaning star....
, G. welwitschii is classified in the section Basimyceliata, which includes species in which the outer part of the mycelial layer do not incorporate sand and encrusting debris. It is further classified in the subsection Laevistomata because its peristome
Peristome
The word peristome is derived from the Greek peri, meaning 'around' or 'about', and stoma, 'mouth'. It is a term used to describe various anatomical features that surround an opening to an organ or structure. The term is used in plants and invertebrate animals, such as in describing the shells of...
(an opening at the top of the spore sac) is even to fibrillose (with fibrils).
Description
The mature fruit body of G. welwitschii is small to medium-sized, with a fornicate spore sac, meaning that the spore sac is raised into the air as the rays press down. Unlike some other earthstar fungi, the mycelialMycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...
layer does not encrust debris as the fruit body develops. The peristome is even, and has an indistinct boundary. The young fruit bodies just prior to opening are found near the surface of the ground, and are rounded, with or without an umbo
Umbo (mycology)
thumb|right|[[Cantharellula umbonata]] has an umbo.thumb|right|The cap of [[Psilocybe makarorae]] is acutely papillate.An umbo is a raised area in the center of a mushroom cap. Caps that possess this feature are called umbonate. Umbos that are sharply pointed are called acute, while those that are...
, and attached to the substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
with a basal mycelial
Mycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...
tuft or cord. The expanded fruit body is small to medium-sized. The fornicate exoperidium (outer peridium
Peridium
The peridium is the protective layer that encloses a mass of spores in fungi. This outer covering is a distinctive feature of the Gasteromycetes.-Description:...
) has the upper, arched part (fibrous and pseudoparenchymatous layers) split to about the half-way point or more into 4–7 rays. The mycelial cup is free (only attached at its base), with 4–7 more or less well-developed lobes corresponding to the 4–7 rays. The width of the fruit body is about 20 –, and in height about 40 – (including the 15–20 mm high mycelial cup). The diameter of the exoperidium is about 39 –.
The pseudoparenchymatous layer (a layer of thin-walled, usually angular, randomly arranged cells that are tightly packed) is initially beige, later brownish, in age dark brown, cracked and if moist reddish-brown. The fibrous layer is beige-colored, with its outer side free from the mycelial layer except at the tips of the rays. The mycelial layer has a beige brown to somewhat yellowish-brown, felted to tufted outer surface, darkening to reddish brown if moist. It is not encrusted with debris, but some debris and sand may adhere. The inner side is smooth, dull to somewhat glossy, and hazelnut brown.
The spore sac is stalked
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
, and roughly spherical, with a diameter of about 8 –. The stalk is short but distinct, up to 1.5 mm (0.0590551181102362 in) high, light beige in color, and sometimes indistinctly developed. The endoperidium (inner peridium) is more or less smooth to the unaided eye, but densely protruding light to grayish-brown hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
l tips are present. The peristome is indistinctly delimited (without distinct boundaries), and the mouth area fibrillose. The columella is not well-developed, and broadly club-shaped to columnar; in cross-section it is whitish to pale beige. The mature gleba
Gleba
Gleba is the fleshy spore-bearing inner mass of fungi such as the puffball or stinkhorn.The gleba is a solid mass of spores, generated within an enclosed area within the sporocarp. The continuous maturity of the sporogenous cells leave the spores behind as a powdery mass that can be easily blown away...
is brown and powdery.
The spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s of Geastrum welwitschii are roughly spherical, sometimes contain an oil droplet, and measure 4.5–5.5 μm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
in diameter. Scanning electron microscopy has revealed that the spore surface is covered with column-like processes, up to 0.45 μm high, that may be more or less confluent.
Similar species
Geastrum welwitschii is morphologicallyMorphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
similar to G. fornicatum
Geastrum fornicatum
Geastrum fornicatum, commonly known as the acrobatic earthstar or the arched earthstar, is an inedible species of mushroom in the family Geastraceae...
in having fornicate, mostly 3–6 rays, of exoperidia and a cup-shaped mycelial layer. Geastrum welwitschii is distinguished from G. fornicatum by its epigeal mycelial cup with a felted or tufted outer surface.
Geastrum welwitschii also has similar morphological characters to G. minimum in having small fruit bodies, whitish spore sacs, and fibrillose peristomes. However G. welwitschii is differentiated from G. minimum by its fornicate, mostly 3–6, rays of the exoperidia, and the mycelial layer that easily loosens from the fibrous layer to form a mycelial cup. G. welwitschii is distinguished from G. entomophilum
Geastrum entomophilum
Geastrum entomophilum is an inedible species of mushroom belonging to the genus Geastrum, or earthstar fungi. Found in northeast Brazil in 2008, the species was found with beetles inhabiting the spore sac, likely contributing to spore dissemination....
by its dark and sessile endoperidium, and smaller spores (2.8–3.5 μm).
According to mycologists Hemmes and Desjardin, the most common earthstar in the coastal Casuarina
Casuarina
Casuarina is a genus of 17 species in the family Casuarinaceae, native to Australasia, southeast Asia, and islands of the western Pacific Ocean. It was once treated as the sole genus in the family, but has been split into three genera .They are evergreen shrubs and trees growing to 35 m tall...
forests of Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
is a species "closely allied" with G. welwitschii, which they name Geastrum aff. welwitschii. It differs from the main species in its much coarser pyramidal warts on the exoperidial surface, a sessile and sac-shaped endoperidial body, and smaller spores. They likened the roughened outer surface of the exoperidium to lychee
Lychee
The lychee is the sole member of the genus Litchi in the soapberry family, Sapindaceae. It is a tropical and subtropical fruit tree native to Southern China and Southeast Asia, and now cultivated in many parts of the world...
fruit.
Habitat and distribution
The fungus is saprobic, and grows on the ground, in leaf litter, or on decomposing wood. It has been collected in Spain, South CarolinaSouth Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, and Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
.