Geastrum quadrifidum
Encyclopedia
Geastrum quadrifidum, commonly known as the rayed earthstar or four-footed earthstar, is an inedible species of mushroom
belonging to the genus Geastrum
, or earthstar fungi. First described scientifically by Christian Hendrik Persoon
in 1794, G. quadrifidum is a cosmopolitan
—but not common—species of Europe, the Americas, Africa, Asia, and Australasia. The fungus is a saprobe, feeding off decomposing organic matter present in the soil and litter
of coniferous forests.
The small, tough, fruit bodies
are grayish-brown balls that are initially enclosed by a skin, or peridium
, made up of four distinct layers of tissue. The outer tissue layer splits to form star-like rays and expose a circular spore
case. Inside the spore case is the gleba
—fertile spore-producing tissue that is white and firm when young, but becomes brown and powdery in age. The grayish-brown spore case is set on a short, slender stalk, and has a well-defined narrow pore at the top where mature spores may escape. Fully expanded, the fruit body reaches dimensions up to 2 – wide and up to about 3 cm (1.2 in) tall. The outer skin is purplish-brown, with four or five cream or yellowish-brown colored rays that have their tips stuck in the substrate
. There is a flat mat of interwoven mycelia between ray tips. The spores are spherical, warty, and have a diameter of up to 6 µm
. Geastrum quadrifidum is one of a number of earthstars whose rays arch downward as they mature, lifting the spore sac upward, high enough to catch air currents that disseminate the spores into new habitats. The species is easily confused with Geastrum fornicatum
, a larger earthstar without a well-defined pore mouth.
published the first official description of Geastrum quadrifidum in 1794, and later sanctioned
this name in his 1801 Synopsis Methodica Fungorum (as Geastrum quadrifidum var. minus, a variety now considered synonymous
with G. quadrifidum). Although the species had been previously described as Lycoperdon coronatum by Jacob Christian Schaeffer (1763) and Giovanni Antonio Scopoli
(1772), then afterward as Geaster coronatus by Joseph Schröter
(1889), the epithet coronatus is not to be used because of the existence of the sanctioned name.
In Japan, G. quadrifidum has occasionally been called "Geastrum minus" (Pers.) G. Cunn. (for example, as in Imai, 1936); within taxonomical terminology, this usage is an auctorum non—a misapplication or misinterpretation of the species name.
According to Stanek's classification of the genus Geastrum, (a classification later endorsed in Sunhede's 1989 monograph
of European Geastrum species), G. quadrifidum belongs in the subsection Glabrostoma of the section Perimyceliata, a grouping of similar Geastrum species that incorporate and encrust debris in the mycelial layer, and have an even peristome
(opening) that is fibrillose (made of more or less parallel thin thread-like filaments). Several common name
s for G. quadrifidum have been suggested, including "rayed earthstar", "four-pointed earthstar" and "four-footed earthstar". Samuel Frederick Gray
called it the "four-cut shell-puff" in his 1821 The Natural Arrangement of British Plants, but the name was not adopted by subsequent authors. The specific epithet quadrifidum is derived from Latin
, and means "four-forks".
is enclosed in the peridium
, a protective structure composed of four layers of tissue: an inner endoperidium, and outer exoperidium that may further be divided into an external mycelial
, a tough and membranous middle fibrillose layer, and an internal fleshy layer (known as the pseudoparenchyma). The immature, unopened fruit body is roughly spherical to somewhat flattened or irregular in shape. It lies partly or wholly submerged, encrusted with debris
. The expanded fruit body is usually taller than it is wide, about 10 – high, with mycelial cup included about 15 –. The exoperidium (the outer tissue layer of the four-layered peridium
) splits in the middle into three to six, but usually four or five rays. The exoperidium is typically fornicate—a structural feature that arises when the mesoperidium separates from the exoperidium, adhering only at the edge. In this way, the endoperidium (the internal tissue layer that encloses the spore sac) is lifted upwards with the downward movement of the rays. In this species, the tips of the rays remain attached to the mycelial layer, which remain attached to the substrate
as a cup in the ground.
Unlike those of some other Geastrum species, the rays of G. quadrifidum are not hygroscopic: they do not open and close in response to changes in humidity. Generally, the rays are broad, but they may seem narrow as their edges are often rolled inwards. The width of the exoperidium (when still attached to the mycelial cup) is 8 –, when fully expanded about 15 –. The pseudoparenchymatous layer when fresh is about 1–2 mm thick, initially whitish, later turning beige to brownish (sometimes over reddish tints), and dark brown when old. In newly expanded specimens this layer is covered with a thin layer of crystals and hypha
e, sometimes forming a pseudoparenchymatous cup or collar that often peels off in patches, when dry shrunken and hard. The fibrous layer is papery to leathery. The inner side, when free from pseudoparenchymatous remnants, is almost white, in age becoming dirty grayish-white and sometimes greenish due to algae; the outer side is initially whitish, somewhat glossy, but in age becomes grayish-white and dull. The mycelial layer has a whitish inner side and is strongly attached to the litter on its outer side. It persists for a long time (1–2-year-old fruit bodies with intact mycelial cups have been found).
The spore sac is variable in shape, ranging from roughly spherical to egg-shaped or irregular, but it is usually taller than it is wide. Its diameter ranges between 3.5 and 16 mm (0.137795275590551 and 0.62992125984252 in), although it is most commonly between 5 and 10 mm (0.196850393700787 and 0.393700787401575 in). An apophysis (a swelling on the underside of the spore sac) is often present. The stalk is visible when the pseudoparenchymatous layer has dried up, and is short but distinct, measuring 1–2.5 mm tall. The color is variable; in dry specimens it is whitish, light beige, beige gray, smoky gray or brownish-gray. The endoperidium in newly expanded fruit bodies is pruinose: covered with a light beige to whitish powder of hyphae and crystalline matter. This powder gradually disappears as the fruit body ages. Its color is highly variable, and both light and dark endoperidia are present. The peristome (a clearly demarcated region encircling the opening of the spore sac) is distinctly delimited, with a disc-like to more or less conical shape. It is lighter in color than the spore sac, and up to 2 mm high. In old specimens, the hyphae around the peristome sometimes stick together to develop radial grooves. The color is variable, but often of grayish or grayish-brown tints, often lighter than the endoperidium. The columella (sterile tissue, usually originating in the base of the gleba
, extending into or through the gleba) is rather weak, more or less columnar to club-shaped, emerging from a more or less bulge-like continuation of the stalk and intruding to about the half or more into the mature gleba. The mature gleba is dark brown. G. quadrifidum is inedible.
of G. quadrifidum have a basal clamp connection
, or they narrow into a hyphal part that ends at a clamp. When they are young, they are more or less ellipsoid to club-shaped, but in age they often become more or less bottle-shaped, ampullaceous or sometimes almost lecythiform, among other shapes; when mature they measure 14–21 x 4.5–7 µm
(excluding the hyphal part). The hyphal part is less than 1–6 x 1–2 µm. The sterigmata (thin projections of the basidia that attach the to spore) are 4–6 µm long and mostly 1–1.5 µm thick. The hyphae located immediately underneath the basidia are thin-walled, 1–2 µm wide, provided with clamps and densely branched. The hyphae of the tramal plates are roughly parallel, thin-walled, 1–2 µm wide, and provided with clamps which may be dilated.
The spores in mass are dark brown when mature. They are spherical, covered with "warts" or verrucae, and measure 5–6 µm in diameter (including ornamentation). The spores often contain a drop of oil. Scanning electron microscopy reveals the verrucae to be up to 0.8 µm long, conical to columnar processes with rounded to almost flattened tips. The apiculus (the part of a spore which attaches to the sterigmata at the end of a basidium) is distinct with radiating ridge-like processes. The young spore is first broadly egg-shaped before becoming roughly spherical in maturity.
The capillitium refers to coarse, late-maturing, thick-walled cells in the gleba that develop pores or slits in their thick secondary walls. The capillitial hyphae are 1.5–9.5 µm wide, thick-walled, often with a narrow lumen
, and with or without surface ornamentation. The columella hyphae are 1.5–14 µm wide (occasionally wider, up to 34 µm), thick-walled, often with narrow lumen. Single thin-walled, about 1.5 µm wide hyphae with clamps can be observed. The endoperidial hyphae are densely interwoven, thick-walled, and about 2–6 µm wide. The whitish powder on newly expanded specimens consists of crystalline matter and thin-walled, 1.5–4 µm wide, branched hyphae with clamps. The peristome hyphae are thick-walled, 2–11 µm wide. The pseudoparenchymatous layer is built up by bladder-like, thin-walled hyphae of varying size. On the surface of newly expanded specimens crystals and thin-walled hyphae of the same kind as on the endoperidium are present. The crystals are calcium oxalate
dihydrate that have the crystalline structure of a pyramid, and are arranged singly or in loose aggregates, 11 to 30 µm in size. The fibrous layer has thick-walled hyphae 1.5–4 µm wide. The mycelial layer in the inner, very thin part (seen as a glossy lining on the fibrous layer of newly expanded fruit bodies) consists of a dense web of thin-walled, 1.5–4 µm wide, clamped hyphae. Thick-walled hyphae are also present, measuring 2–11 (sometimes up to 19) µm wide. The outer part (the mycelial cup) consists of thick-walled, branched and densely interwoven hyphae (often with a narrow lumen) that measure 1.5–4 µm wide.
, which is larger—up to 15 cm (5.9 in)—and has smaller spores (4–5 μm in diameter). Geastrum minimum, although small like G. quadrifidum, is distinguished by having more rays (usually more than seven), and it is not fornicate. Also, its mycelial layer is attached to the fibrous layer for a long time, without forming a mycelial cup like G. quadrifidum. The Chilean species G. jurei
does not have a clearly demarcated peristome.
Geastrum quadrifidum is also similar to G. dissimile, G. leptospermum
, and G. welwitschii
in its fruit body morphology
, especially the exoperidial rays, endoperidial body, and peristome. Geastrum dissimile differs from G. quadrifidum by its often sulcate or silky fimbriate, smooth peristome, and slightly smaller spores (4–5 μm in diameter). Geastrum leptospermum can be distinguished from G. quadrifidum by its smaller spores (2–3 μm in diameter), and by its preference for growing in mosses on tree trunks. G. welwitschii differs from G. quadrifidum by its epigeal
mycelial cup with a felted or tufted outer surface, and indistinctly delimited peristome.
, Norway, Poland, and Sweden. In Asia, it has been collected in China and Japan. The North American distribution extends from Canada south to Mexico, and includes Hawaii. It is also found in Australia and New Zealand, South Africa, and South America. Because of its rarity, it has been placed on the Regional Red List
s of several European countries, including Montenegro
, Denmark, Norway, and Poland.
Like most earthstars, G. quadrifidum is a saprobic fungus, and spends most of its life cycle
as thin strands of mycelium
, deriving nutrients by decomposing leaf litter
and similar detritus
, converting it to humus and mineralizing
organic matter in the soil. The fungal fruit bodies are generally found in coniferous woodland, where they appear in summer and autumn. In Mexico, it was found in tropical thorn forest
and pine-oak forest
in the summer. In Britain, all collections have been made in beech
forest on calcareous
soil.
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
belonging to 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....
, or earthstar fungi. First described scientifically by Christian Hendrik Persoon
Christian Hendrik Persoon
Christiaan Hendrik Persoon was a mycologist who made additions to Linnaeus' mushroom taxonomy.-Early life:...
in 1794, G. quadrifidum is a cosmopolitan
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
—but not common—species of Europe, the Americas, Africa, Asia, and Australasia. The fungus is a saprobe, feeding off decomposing organic matter present in the soil and litter
Forest floor
The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface...
of coniferous forests.
The small, tough, fruit bodies
Sporocarp (fungi)
In fungi, the sporocarp is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne...
are grayish-brown balls that are initially enclosed by a skin, or 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:...
, made up of four distinct layers of tissue. The outer tissue layer splits to form star-like rays and expose a circular 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...
case. Inside the spore case is 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...
—fertile spore-producing tissue that is white and firm when young, but becomes brown and powdery in age. The grayish-brown spore case is set on a short, slender stalk, and has a well-defined narrow pore at the top where mature spores may escape. Fully expanded, the fruit body reaches dimensions up to 2 – wide and up to about 3 cm (1.2 in) tall. The outer skin is purplish-brown, with four or five cream or yellowish-brown colored rays that have their tips stuck in 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...
. There is a flat mat of interwoven mycelia between ray tips. The spores are spherical, warty, and have a diameter of up to 6 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...
. Geastrum quadrifidum is one of a number of earthstars whose rays arch downward as they mature, lifting the spore sac upward, high enough to catch air currents that disseminate the spores into new habitats. The species is easily confused with Geastrum 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...
, a larger earthstar without a well-defined pore mouth.
Taxonomy and naming
The Dutch mycologist Christian Hendrik PersoonChristian Hendrik Persoon
Christiaan Hendrik Persoon was a mycologist who made additions to Linnaeus' mushroom taxonomy.-Early life:...
published the first official description of Geastrum quadrifidum in 1794, and later sanctioned
Sanctioned name
In mycology, a sanctioned name is a name that was adopted in certain works of Christiaan Hendrik Persoon or Elias Magnus Fries, which are considered major points in fungal taxonomy.-Definition and effects:...
this name in his 1801 Synopsis Methodica Fungorum (as Geastrum quadrifidum var. minus, a variety now considered synonymous
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...
with G. quadrifidum). Although the species had been previously described as Lycoperdon coronatum by Jacob Christian Schaeffer (1763) and Giovanni Antonio Scopoli
Giovanni Antonio Scopoli
Giovanni Antonio Scopoli was an Italian physician and naturalist.-Biography:...
(1772), then afterward as Geaster coronatus by Joseph Schröter
Joseph Schröter
Joseph Schröter was a noted German mycologist, doctor and scientist. During his lifetime, he wrote several books and texts, and discovered and described many species of flora and fungi...
(1889), the epithet coronatus is not to be used because of the existence of the sanctioned name.
In Japan, G. quadrifidum has occasionally been called "Geastrum minus" (Pers.) G. Cunn. (for example, as in Imai, 1936); within taxonomical terminology, this usage is an auctorum non—a misapplication or misinterpretation of the species name.
According to Stanek's classification of the genus Geastrum, (a classification later endorsed in Sunhede's 1989 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 European Geastrum species), G. quadrifidum belongs in the subsection Glabrostoma of the section Perimyceliata, a grouping of similar Geastrum species that incorporate and encrust debris in the mycelial layer, and have an even 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...
(opening) that is fibrillose (made of more or less parallel thin thread-like filaments). Several common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
s for G. quadrifidum have been suggested, including "rayed earthstar", "four-pointed earthstar" and "four-footed earthstar". Samuel Frederick Gray
Samuel Frederick Gray
Samuel Frederick Gray was a British botanist, mycologist, and pharmacologist. He was the father of the zoologists John Edward Gray and George Robert Gray.-Background:...
called it the "four-cut shell-puff" in his 1821 The Natural Arrangement of British Plants, but the name was not adopted by subsequent authors. The specific epithet quadrifidum is derived from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
, and means "four-forks".
Description
As in all Geastrum fungi, the internal spore-producing glebaGleba
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 enclosed in 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:...
, a protective structure composed of four layers of tissue: an inner endoperidium, and outer exoperidium that may further be divided into an external 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...
, a tough and membranous middle fibrillose layer, and an internal fleshy layer (known as the pseudoparenchyma). The immature, unopened fruit body is roughly spherical to somewhat flattened or irregular in shape. It lies partly or wholly submerged, encrusted with debris
Forest floor
The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface...
. The expanded fruit body is usually taller than it is wide, about 10 – high, with mycelial cup included about 15 –. The exoperidium (the outer tissue layer of the four-layered 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 in the middle into three to six, but usually four or five rays. The exoperidium is typically fornicate—a structural feature that arises when the mesoperidium separates from the exoperidium, adhering only at the edge. In this way, the endoperidium (the internal tissue layer that encloses the spore sac) is lifted upwards with the downward movement of the rays. In this species, the tips of the rays remain attached to the mycelial layer, which remain 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...
as a cup in the ground.
Unlike those of some other Geastrum species, the rays of G. quadrifidum are not hygroscopic: they do not open and close in response to changes in humidity. Generally, the rays are broad, but they may seem narrow as their edges are often rolled inwards. The width of the exoperidium (when still attached to the mycelial cup) is 8 –, when fully expanded about 15 –. The pseudoparenchymatous layer when fresh is about 1–2 mm thick, initially whitish, later turning beige to brownish (sometimes over reddish tints), and dark brown when old. In newly expanded specimens this layer is covered with a thin layer of crystals and 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...
e, sometimes forming a pseudoparenchymatous cup or collar that often peels off in patches, when dry shrunken and hard. The fibrous layer is papery to leathery. The inner side, when free from pseudoparenchymatous remnants, is almost white, in age becoming dirty grayish-white and sometimes greenish due to algae; the outer side is initially whitish, somewhat glossy, but in age becomes grayish-white and dull. The mycelial layer has a whitish inner side and is strongly attached to the litter on its outer side. It persists for a long time (1–2-year-old fruit bodies with intact mycelial cups have been found).
The spore sac is variable in shape, ranging from roughly spherical to egg-shaped or irregular, but it is usually taller than it is wide. Its diameter ranges between 3.5 and 16 mm (0.137795275590551 and 0.62992125984252 in), although it is most commonly between 5 and 10 mm (0.196850393700787 and 0.393700787401575 in). An apophysis (a swelling on the underside of the spore sac) is often present. The stalk is visible when the pseudoparenchymatous layer has dried up, and is short but distinct, measuring 1–2.5 mm tall. The color is variable; in dry specimens it is whitish, light beige, beige gray, smoky gray or brownish-gray. The endoperidium in newly expanded fruit bodies is pruinose: covered with a light beige to whitish powder of hyphae and crystalline matter. This powder gradually disappears as the fruit body ages. Its color is highly variable, and both light and dark endoperidia are present. The peristome (a clearly demarcated region encircling the opening of the spore sac) is distinctly delimited, with a disc-like to more or less conical shape. It is lighter in color than the spore sac, and up to 2 mm high. In old specimens, the hyphae around the peristome sometimes stick together to develop radial grooves. The color is variable, but often of grayish or grayish-brown tints, often lighter than the endoperidium. The columella (sterile tissue, usually originating in the base of 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...
, extending into or through the gleba) is rather weak, more or less columnar to club-shaped, emerging from a more or less bulge-like continuation of the stalk and intruding to about the half or more into the mature gleba. The mature gleba is dark brown. G. quadrifidum is inedible.
Microscopic characteristics
The basidiaBasidium
thumb|right|500px|Schematic showing a basidiomycete mushroom, gill structure, and spore-bearing basidia on the gill margins.A basidium is a microscopic, spore-producing structure found on the hymenophore of fruiting bodies of basidiomycete fungi. The presence of basidia is one of the main...
of G. quadrifidum have a basal clamp connection
Clamp connection
A clamp connection is a structure formed by growing hyphal cells of certain fungi. It is created to ensure each septum, or segment of hypha separated by crossed walls, receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types...
, or they narrow into a hyphal part that ends at a clamp. When they are young, they are more or less ellipsoid to club-shaped, but in age they often become more or less bottle-shaped, ampullaceous or sometimes almost lecythiform, among other shapes; when mature they measure 14–21 x 4.5–7 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...
(excluding the hyphal part). The hyphal part is less than 1–6 x 1–2 µm. The sterigmata (thin projections of the basidia that attach the to spore) are 4–6 µm long and mostly 1–1.5 µm thick. The hyphae located immediately underneath the basidia are thin-walled, 1–2 µm wide, provided with clamps and densely branched. The hyphae of the tramal plates are roughly parallel, thin-walled, 1–2 µm wide, and provided with clamps which may be dilated.
The spores in mass are dark brown when mature. They are spherical, covered with "warts" or verrucae, and measure 5–6 µm in diameter (including ornamentation). The spores often contain a drop of oil. Scanning electron microscopy reveals the verrucae to be up to 0.8 µm long, conical to columnar processes with rounded to almost flattened tips. The apiculus (the part of a spore which attaches to the sterigmata at the end of a basidium) is distinct with radiating ridge-like processes. The young spore is first broadly egg-shaped before becoming roughly spherical in maturity.
The capillitium refers to coarse, late-maturing, thick-walled cells in the gleba that develop pores or slits in their thick secondary walls. The capillitial hyphae are 1.5–9.5 µm wide, thick-walled, often with a narrow lumen
Lumen (anatomy)
A lumen in biology is the inside space of a tubular structure, such as an artery or intestine...
, and with or without surface ornamentation. The columella hyphae are 1.5–14 µm wide (occasionally wider, up to 34 µm), thick-walled, often with narrow lumen. Single thin-walled, about 1.5 µm wide hyphae with clamps can be observed. The endoperidial hyphae are densely interwoven, thick-walled, and about 2–6 µm wide. The whitish powder on newly expanded specimens consists of crystalline matter and thin-walled, 1.5–4 µm wide, branched hyphae with clamps. The peristome hyphae are thick-walled, 2–11 µm wide. The pseudoparenchymatous layer is built up by bladder-like, thin-walled hyphae of varying size. On the surface of newly expanded specimens crystals and thin-walled hyphae of the same kind as on the endoperidium are present. The crystals are calcium oxalate
Calcium oxalate
Calcium oxalate is a chemical compound that forms needle-shaped crystals, known in plants as raphides. A major constituent of human kidney stones, the chemical is also found in beerstone, a scale that forms on containers used in breweries...
dihydrate that have the crystalline structure of a pyramid, and are arranged singly or in loose aggregates, 11 to 30 µm in size. The fibrous layer has thick-walled hyphae 1.5–4 µm wide. The mycelial layer in the inner, very thin part (seen as a glossy lining on the fibrous layer of newly expanded fruit bodies) consists of a dense web of thin-walled, 1.5–4 µm wide, clamped hyphae. Thick-walled hyphae are also present, measuring 2–11 (sometimes up to 19) µm wide. The outer part (the mycelial cup) consists of thick-walled, branched and densely interwoven hyphae (often with a narrow lumen) that measure 1.5–4 µm wide.
Similar species
Geastrum quadrifidum is readily confused with G. fornicatumGeastrum fornicatum
Geastrum fornicatum, commonly known as the acrobatic earthstar or the arched earthstar, is an inedible species of mushroom in the family Geastraceae...
, which is larger—up to 15 cm (5.9 in)—and has smaller spores (4–5 μm in diameter). Geastrum minimum, although small like G. quadrifidum, is distinguished by having more rays (usually more than seven), and it is not fornicate. Also, its mycelial layer is attached to the fibrous layer for a long time, without forming a mycelial cup like G. quadrifidum. The Chilean species G. jurei
Geastrum jurei
Geastrum jurei is a species of fungus in the Geastrales, or earthstar fungi. It is known only from Algarrobo, in the Valparaíso province of Chile...
does not have a clearly demarcated peristome.
Geastrum quadrifidum is also similar to G. dissimile, G. leptospermum
Geastrum leptospermum
Geastrum leptospermum is a species of fungus in the Geastraceae family. It was first described scientifically by American mycologist George F. Atkinson in 1903...
, and G. welwitschii
Geastrum welwitschii
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...
in its fruit body morphology
Morphology (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....
, especially the exoperidial rays, endoperidial body, and peristome. Geastrum dissimile differs from G. quadrifidum by its often sulcate or silky fimbriate, smooth peristome, and slightly smaller spores (4–5 μm in diameter). Geastrum leptospermum can be distinguished from G. quadrifidum by its smaller spores (2–3 μm in diameter), and by its preference for growing in mosses on tree trunks. G. welwitschii differs from G. quadrifidum by its epigeal
Epigeal
Epigeal, epigean, epigeic and epigeous are biological terms describing an organism's activity above the soil surface.In botany, a seed is described as epigeal when the cotyledons of the germinating seed expand, throw off the seed shell and become photosynthetic above the ground...
mycelial cup with a felted or tufted outer surface, and indistinctly delimited peristome.
Distribution, ecology, and habitat
Although Geastrum quadrifidum has a wide distribution, it is not a common species. European countries from which the fungus has been reported include Belgium, Denmark, France, Germany, MontenegroMontenegro
Montenegro Montenegrin: Crna Gora Црна Гора , meaning "Black Mountain") is a country located in Southeastern Europe. It has a coast on the Adriatic Sea to the south-west and is bordered by Croatia to the west, Bosnia and Herzegovina to the northwest, Serbia to the northeast and Albania to the...
, Norway, Poland, and Sweden. In Asia, it has been collected in China and Japan. The North American distribution extends from Canada south to Mexico, and includes Hawaii. It is also found in Australia and New Zealand, South Africa, and South America. Because of its rarity, it has been placed on the Regional Red List
Regional Red List
A Regional Red List is a report of the threatened status of species within a certain country or region. It is based on the IUCN Red List of Threatened Species, an inventory of the conservation status of species on a global scale...
s of several European countries, including Montenegro
Montenegro
Montenegro Montenegrin: Crna Gora Црна Гора , meaning "Black Mountain") is a country located in Southeastern Europe. It has a coast on the Adriatic Sea to the south-west and is bordered by Croatia to the west, Bosnia and Herzegovina to the northwest, Serbia to the northeast and Albania to the...
, Denmark, Norway, and Poland.
Like most earthstars, G. quadrifidum is a saprobic fungus, and spends most of its life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
as thin strands of mycelium
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...
, deriving nutrients by decomposing leaf litter
Forest floor
The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface...
and similar detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
, converting it to humus and mineralizing
Mineralization (soil)
Mineralization in soil science, is when the chemical compounds in organic matter decompose or are oxidized into plant-accessible forms,. Mineralization is the opposite of immobilization....
organic matter in the soil. The fungal fruit bodies are generally found in coniferous woodland, where they appear in summer and autumn. In Mexico, it was found in tropical thorn forest
Thorn forest
A thorn forest is a dense, scrublike vegetation characteristic of dry subtropical and warm temperate areas with a seasonal rainfall averaging . This vegetation covers a large part of southwestern North America and southwestern Africa and smaller areas in Africa, South America, and Australia...
and pine-oak forest
Sierra Madre Oriental pine-oak forests
The Sierra Madre Oriental pine-oak forests are a subtropical coniferous forest ecoregion of northeastern and Central Mexico, extending into the state of Texas in the United States.-Setting:...
in the summer. In Britain, all collections have been made in beech
Beech
Beech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...
forest on calcareous
Calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...
soil.
External links
- Mushroom Observer Images