Limnoperdaceae
Encyclopedia
Limnoperdon is a fungal genus
in the monotypic family
Limnoperdaceae. The genus is also monotypic, as it contains a single species, the aquatic fungus Limnoperdon incarnatum. The species, described as new to science in 1976, produces fruit bodies that lack specialized structures such as a stem
, cap
and gills common in mushroom
s. Rather, the fruit bodies—described as aquatic or floating puffball
s—are small balls (0.5–1 mm diameter) of loosely interwoven hypha
e. The balls float on the surface of the water above submerged twigs. Experimental observations on the development
of the fruit body, based on the growth on the fungus in pure culture, suggest that a thin strand of mycelium
tethers the ball above water while it matures. Fruit bodies start out as a tuft of hyphae, then become cup-shaped, and eventually enclose around a single chamber that contains reddish spore
s. Initially discovered in a marsh in the state of Washington, the fungus has since been collected in Japan, South Africa, and Canada.
". The holotype
is located in the University of Washington
Mycological Herbarium. An isotype (duplicate of the holotype specimen) is located in the Herbarium of the University of El Salvador
in San Salvador
.
Limnoperdon incarnatum was originally thought to be associated with the Gasteromycetes, an artificial assemblage of species united by the fact that their spore
s mature inside the fruit bodies and are not forcibly discharged from the basidia. Other morphologically
similar genera include the Gasterella of the family Gasterellaceae
, and the Protogaster of the family Protogastraceae
; however, it was excluded from these genera because of significant differences in spore
color and structure, presence of clamp connection
s, and structure of the basidia
. For these reasons the new family Limnoperdaceae was described to contain the new species, and it was classified along the Protogastraceae in the (now defunct) order Protogastrales. More recently, molecular phylogenetics has been to used to clarify the relationship Limnoperdon with other fungi. In 2001, David Hibbett and Manfred Binder established the membership of Limnoperdon incarnatum in the euagarics clade
, a phylogenetically related group of species traditionally forming the order Agaricales
. Additional molecular studies have placed Limnoperdaceae in the pluteoid clade of the Agaricales, a grouping that includes the families Pluteaceae
, Amanitaceae
, and Pleurotaceae
; other studies that used comparisons of ribosomal DNA
sequences placed Limnoperdon near the gilled genera Melanoleuca
or Resupinatus
, of the Tricholomataceae
family.
A 2007 field study that used molecular techniques to survey aquatic fungal taxa
in a small springbrook in Valley Spring, Southern Ontario
, Canada discovered many fungal taxa with high genetic affinity to Limnoperdon incarnatum, which suggests that a closely related species may also be common in streams.
e), and that the spores are reddish. The fungus has been described as an "aquatic puffball", although a later review considered "floating puffball" to be a more apt descriptor.
The fruit bodies of L. incarnatum are tiny, oval to roughly spherical, and measure 35–1250 by 200–450 μm
. The floating balls are sometimes enclosed in a loose subiculum, with a whitish surface that is byssoid (consisting of fine threads). The peridium
(the outer protective tissue layer) is 18–30 μm thick, byssoid, and made of clamped hyphae typically 2.5–4 μm in diameter intertwined with dendrophyses (irregularly branched cystidia) 1 μm in diameter. The surface of the peridium is hydrophobic, a feature that helps keep water off the growing hymenium during its development, and gives the fruit body buoyancy.
The gleba
is a single chamber, reddish in color, with a cavity that has an oblate spheroid shape. Initially empty, in maturity it is filled with spores that measure 330–1220 by 180–420 μm. The smooth inner surface of the chamber comprises the fertile spore-bearing tissue (the hymenium
). The basidia (spore-bearing cells)—conspicuous when viewed under the microscope—are hyaline
(translucent), more or less club-shaped, and usually have basal and apical swellings separated by a narrow strip of variable length. The basidia are four-spored, and have inflated sterigmata with a central constriction. The basidia measure 20–90 (typically 25–55) μm long by 8–10 μm thick. Reddish in mass, the spores are obovate (egg-shaped, with the broad extremity located away from the base), smooth, thick-walled, and measure 11–16 (typically 12–15) by 7–10 μm. They have a beaked pedicel
that is 2–4 by 2–5 μm, and a basal germ pore
.
es that contained submerged hardwood
twigs previously collected from a marsh next to a playground on the south shore of Lake Union
in Seattle, Washington
. After the initial 1976 publication, L. incarnatum was reported the following year when Keisuke Tubaki recovered it from wood blocks submerged in brackish water
in Japan; scientists Seiya Ito and T. Yokoyama later reported collecting it in Japanese rice paddy fields. Later surveys uncovered the fungus in several localities in South Africa and in freshwater ponds in Canada.
containing growth medium
with an extract of horse dung. The tips of the hyphae were used to obtain axenic
cultures; the fungus can grow on a variety of media commonly used to grow fungi in the laboratory. Depending on the composition of the growth media, fruit bodies were formed as early as eight days after initiating, when grown at 20 °C (68 °F) and under dim light. When minute agar blocks containing mycelium
were submerged in distilled water
, mycelial strands grew towards the water surface and eventually gave rise to floating fruit bodies connected to the parent agar block by strands of hyphae.
Mycologist Dennis McCabe studied the development
of the fruit body using specimens grown in pure culture
. Starting out as a hyphal tuft, the fungus grows into a cup shape before eventually closing in completely to create the spherical structure of the mature fruit body. When the fungus is in the cup stage, the exposed hymenium
is immature; typically, spores develop after the fruit body is fully closed. In some cases, the fruit body stops developing at the cup stage while the hymenium continues to mature. This results in a cup-shaped fungus with an exposed layer of basidia bearing normal and mature spores. Limnoperdon incarnatum is a structurally simple fungus, and relatively easy to grow in culture, suggesting it may have potential as a model organism
for fruit body development in general. Under the experimental conditions used, fruit bodies matured to produce spores about 72 hours after the fungus started growing. The aborted cups resemble the sporocarps of the cyphelloid fungi
, but can be distinguished by their orthotrophic
spore attachment and the lack of ballistospory
(forceful spore discharge). McCabe and Escobar later suggested that the fungus may have evolved the loss of ballistospory by being compensated with the cup-shaped fruit body closing at maturity. Halocyphina villosa is another small cup-shaped Basidiomycete fungus that has adapted to a marine environment; in contrast to L. incarnatum, however, it starts out with a closed fruit body that later opens up to become cup-shaped.
Although it is not known with certainty how the spores are dispersed, they may disperse passively in the water, or a mature spore-containing fruit body may float on the water surface for dispersal. L. incarnatum is homothallic
, a mode of reproduction
commonly employed by marine fungi that may confer a competitive advantage
in marine environments.
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...
in the monotypic family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Limnoperdaceae. The genus is also monotypic, as it contains a single species, the aquatic fungus Limnoperdon incarnatum. The species, described as new to science in 1976, produces fruit bodies that lack specialized structures such as a stem
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...
, cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
and gills common in mushroom
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...
s. Rather, the fruit bodies—described as aquatic or floating puffball
Puffball
A puffball is a member of any of several groups of fungus in the division Basidiomycota. The puffballs were previously treated as a taxonomic group called the Gasteromycetes or Gasteromycetidae, but they are now known to be a polyphyletic assemblage. The distinguishing feature of all puffballs is...
s—are small balls (0.5–1 mm diameter) of loosely interwoven 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. The balls float on the surface of the water above submerged twigs. Experimental observations on the development
Morphogenesis
Morphogenesis , is the biological process that causes an organism to develop its shape...
of the fruit body, based on the growth on the fungus in pure culture, suggest that a thin strand 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...
tethers the ball above water while it matures. Fruit bodies start out as a tuft of hyphae, then become cup-shaped, and eventually enclose around a single chamber that contains reddish 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. Initially discovered in a marsh in the state of Washington, the fungus has since been collected in Japan, South Africa, and Canada.
Taxonomy, classification and phylogeny
The family, genus and species were first described in a 1976 publication by mycologist Gustavo Escobar, who, in the fall of 1974, found them as part of "a class project to find and isolate phycomycetesPhycomycetes
Phycomycetes is an obsolete taxon for certain fungi with nonseptate hyphae.These fungi are currently classified under Zygomycota....
". The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
is located in the University of Washington
University of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...
Mycological Herbarium. An isotype (duplicate of the holotype specimen) is located in the Herbarium of the University of El Salvador
University of El Salvador
The University of El Salvador or Universidad de El Salvador is the oldest and one of the most prominent university institutions in El Salvador. It serves as the national university of the country...
in San Salvador
San Salvador
The city of San Salvador the capital and largest city of El Salvador, which has been designated a Gamma World City. Its complete name is La Ciudad de Gran San Salvador...
.
Limnoperdon incarnatum was originally thought to be associated with the Gasteromycetes, an artificial assemblage of species united by the fact that their 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 mature inside the fruit bodies and are not forcibly discharged from the basidia. Other morphologically
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....
similar genera include the Gasterella of the family Gasterellaceae
Gasterellaceae
Gasterellaceae is a family of fungi in the order Boletales. It contains the single genus Gasterella, which in turn contains the single species Gasterella luteophila, found in the USA. The genus and species was described by American mycologists Sanford Myron Zeller and Leva Belle Walker in 1935; the...
, and the Protogaster of the family Protogastraceae
Protogastraceae
Protogastraceae is a family of fungi in the order Boletales that contains the single genus Protogaster. The genus in turn contains the single species Protogaster rhizophilus, found on the roots of Viola in the USA. The family was described by American mycologist Sanford Myron Zeller in 1934, the...
; however, it was excluded from these genera because of significant differences in 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...
color and structure, presence of 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...
s, and structure of the basidia
Basidium
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...
. For these reasons the new family Limnoperdaceae was described to contain the new species, and it was classified along the Protogastraceae in the (now defunct) order Protogastrales. More recently, molecular phylogenetics has been to used to clarify the relationship Limnoperdon with other fungi. In 2001, David Hibbett and Manfred Binder established the membership of Limnoperdon incarnatum in the euagarics clade
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
, a phylogenetically related group of species traditionally forming the order Agaricales
Agaricales
The fungal order Agaricales, also known as gilled mushrooms , or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13000 described species, along with five extinct genera known only from the fossil record...
. Additional molecular studies have placed Limnoperdaceae in the pluteoid clade of the Agaricales, a grouping that includes the families Pluteaceae
Pluteaceae
The Pluteaceae are a family of small to medium-sized mushrooms which have free gill attachment and pink spores. Members of Pluteaceae can be mistaken for members of Entolomatacae but can be distinguished by their angled spores and attached gills...
, Amanitaceae
Amanitaceae
Amanitaceae are a family of fungi or mushrooms. The family, also commonly called the Amanita family, is in order Agaricales, gilled mushrooms...
, and Pleurotaceae
Pleurotaceae
Pleurotaceae are a family of small to medium sized mushrooms which have white spores. The family contains 6 genera and 94 species. Members of Pleurotaceae can be mistaken for members of Omphalotaceae...
; other studies that used comparisons of ribosomal DNA
Ribosomal DNA
Ribosomal DNA codes for ribosomal RNA. The ribosome is an intracellular macromolecule that produces proteins or polypeptide chains. The ribosome itself consists of a composite of proteins and RNA. As shown in the figure, rDNA consists of a tandem repeat of a unit segment, an operon, composed of...
sequences placed Limnoperdon near the gilled genera Melanoleuca
Melanoleuca
Melanoleuca is a genus of mushrooms in the Tricholomataceae family. Most are small to medium sized, white to brown, with white spores and close gills. They grow directly from the ground, have a nearly flat cap and a tough thin stem. The spores of members of Melanoleuca are ornamented with...
or Resupinatus
Resupinatus
Resupinatus is a genus of fungi in the family Tricholomataceae. Species are saprobic, and often found growing on the underside of decaying wood. The generic name is derived from the Latin resupin .-Description:...
, of the Tricholomataceae
Tricholomataceae
The Tricholomataceae are a large family of mushrooms within the Agaricales. A classic "wastebasket taxon", the Tricholomataceae is inclusive of any white-, yellow-, or pink-spored genera in the Agaricales not already classified as belonging to the Amanitaceae, Lepiotaceae, Hygrophoraceae,...
family.
A 2007 field study that used molecular techniques to survey aquatic fungal taxa
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
in a small springbrook in Valley Spring, Southern Ontario
Southern Ontario
Southern Ontario is a region of the province of Ontario, Canada that lies south of the French River and Algonquin Park. Depending on the inclusion of the Parry Sound and Muskoka districts, its surface area would cover between 14 to 15% of the province. It is the southernmost region of...
, Canada discovered many fungal taxa with high genetic affinity to Limnoperdon incarnatum, which suggests that a closely related species may also be common in streams.
Description
The genus description is similar to the family description, but further specifies that the fruit bodies float, are sometimes embedded in a loose subiculum (a woolly or net-like growth of hyphaHypha
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), and that the spores are reddish. The fungus has been described as an "aquatic puffball", although a later review considered "floating puffball" to be a more apt descriptor.
The fruit bodies of L. incarnatum are tiny, oval to roughly spherical, and measure 35–1250 by 200–450 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...
. The floating balls are sometimes enclosed in a loose subiculum, with a whitish surface that is byssoid (consisting of fine threads). 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:...
(the outer protective tissue layer) is 18–30 μm thick, byssoid, and made of clamped hyphae typically 2.5–4 μm in diameter intertwined with dendrophyses (irregularly branched cystidia) 1 μm in diameter. The surface of the peridium is hydrophobic, a feature that helps keep water off the growing hymenium during its development, and gives the fruit body buoyancy.
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...
is a single chamber, reddish in color, with a cavity that has an oblate spheroid shape. Initially empty, in maturity it is filled with spores that measure 330–1220 by 180–420 μm. The smooth inner surface of the chamber comprises the fertile spore-bearing tissue (the hymenium
Hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...
). The basidia (spore-bearing cells)—conspicuous when viewed under the microscope—are hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
(translucent), more or less club-shaped, and usually have basal and apical swellings separated by a narrow strip of variable length. The basidia are four-spored, and have inflated sterigmata with a central constriction. The basidia measure 20–90 (typically 25–55) μm long by 8–10 μm thick. Reddish in mass, the spores are obovate (egg-shaped, with the broad extremity located away from the base), smooth, thick-walled, and measure 11–16 (typically 12–15) by 7–10 μm. They have a beaked pedicel
Pedicel (botany)
A pedicel is a stem that attaches single flowers to the main stem of the inflorescence. It is the branches or stalks that hold each flower in an inflorescence that contains more than one flower....
that is 2–4 by 2–5 μm, and a basal germ pore
Germ pore
A germ pore is a small pore in the outer wall of a fungal spore through which the germ tube exits upon germination. It can be apical or eccentric in its location, and, on light microscopy, may be visualized as a lighter coloured area on the cell wall....
.
Habitat and distribution
The species was originally discovered floating in petri dishPetri dish
A Petri dish is a shallow glass or plastic cylindrical lidded dish that biologists use to culture cells or small moss plants. It was named after German bacteriologist Julius Richard Petri, who invented it when working as an assistant to Robert Koch...
es that contained submerged hardwood
Hardwood
Hardwood is wood from angiosperm trees . It may also be used for those trees themselves: these are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.Hardwood contrasts with softwood...
twigs previously collected from a marsh next to a playground on the south shore of Lake Union
Lake Union
Lake Union is a freshwater lake entirely within the Seattle, Washington city limits.-Origins:A glacial lake, its basin was dug 12,000 years ago by the Vashon glacier, which also created Lake Washington and Seattle's Green, Bitter, and Haller Lakes.-Name:...
in Seattle, Washington
Seattle, Washington
Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...
. After the initial 1976 publication, L. incarnatum was reported the following year when Keisuke Tubaki recovered it from wood blocks submerged in brackish water
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
in Japan; scientists Seiya Ito and T. Yokoyama later reported collecting it in Japanese rice paddy fields. Later surveys uncovered the fungus in several localities in South Africa and in freshwater ponds in Canada.
Development
Escobar grew cultures of the fungus by placing fresh fruit bodies on agarAgar
Agar or agar-agar is a gelatinous substance derived from a polysaccharide that accumulates in the cell walls of agarophyte red algae. Throughout history into modern times, agar has been chiefly used as an ingredient in desserts throughout Asia and also as a solid substrate to contain culture medium...
containing growth medium
Growth medium
A growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or cells, or small plants like the moss Physcomitrella patens.There are different types of media for growing different types of cells....
with an extract of horse dung. The tips of the hyphae were used to obtain axenic
Axenic
In biology, axenic describes a culture of an organism that is entirely free of all other "contaminating" organisms. The earliest axenic cultures were of bacteria or unicellular eukaryotes, but axenic cultures of many multicellular organisms are also possible...
cultures; the fungus can grow on a variety of media commonly used to grow fungi in the laboratory. Depending on the composition of the growth media, fruit bodies were formed as early as eight days after initiating, when grown at 20 °C (68 °F) and under dim light. When minute agar blocks containing 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...
were submerged in distilled water
Distilled water
Distilled water is water that has many of its impurities removed through distillation. Distillation involves boiling the water and then condensing the steam into a clean container.-History:...
, mycelial strands grew towards the water surface and eventually gave rise to floating fruit bodies connected to the parent agar block by strands of hyphae.
Mycologist Dennis McCabe studied the development
Morphogenesis
Morphogenesis , is the biological process that causes an organism to develop its shape...
of the fruit body using specimens grown in pure culture
Microbiological culture
A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory conditions. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested,...
. Starting out as a hyphal tuft, the fungus grows into a cup shape before eventually closing in completely to create the spherical structure of the mature fruit body. When the fungus is in the cup stage, the exposed hymenium
Hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...
is immature; typically, spores develop after the fruit body is fully closed. In some cases, the fruit body stops developing at the cup stage while the hymenium continues to mature. This results in a cup-shaped fungus with an exposed layer of basidia bearing normal and mature spores. Limnoperdon incarnatum is a structurally simple fungus, and relatively easy to grow in culture, suggesting it may have potential as a model organism
Model organism
A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. Model organisms are in vivo models and are widely used to...
for fruit body development in general. Under the experimental conditions used, fruit bodies matured to produce spores about 72 hours after the fungus started growing. The aborted cups resemble the sporocarps of the cyphelloid fungi
Cyphelloid fungi
The cyphelloid fungi are a group of fungi in the Basidiomycota that have disc-, tube-, or cup-shaped basidiocarps , resembling species of discomycetes in the Ascomycota...
, but can be distinguished by their orthotrophic
Orthotropic material
An orthotropic material has two or three mutually orthogonal twofold axes of rotational symmetry so that its mechanical properties are, in general, different along each axis. Orthotropic materials are thus anisotropic; their properties depend on the direction in which they are measured...
spore attachment and the lack of ballistospory
Ballistospore
A spore that is shot off. In fungi most types of basidiospores, formed on basidia are discharged into the air from the tips of sterigmata. These actively discharged spores are a type of ballistospore....
(forceful spore discharge). McCabe and Escobar later suggested that the fungus may have evolved the loss of ballistospory by being compensated with the cup-shaped fruit body closing at maturity. Halocyphina villosa is another small cup-shaped Basidiomycete fungus that has adapted to a marine environment; in contrast to L. incarnatum, however, it starts out with a closed fruit body that later opens up to become cup-shaped.
Although it is not known with certainty how the spores are dispersed, they may disperse passively in the water, or a mature spore-containing fruit body may float on the water surface for dispersal. L. incarnatum is homothallic
Homothallic
Homothallic refers to the possession, within a single organism, of the resources to reproduce sexually.It can be contrasted to heterothallic.It is often used to categorize fungi. In yeast, heterothallic cells have mating types a and α...
, a mode of reproduction
Mating in fungi
Mating in fungi is a complex process governed by mating types. Research on fungal mating has focused on only a few model species. Since not all of the fungi reproduce sexually and many that do are isogamous, the terms male and female do not apply to this kingdom...
commonly employed by marine fungi that may confer a competitive advantage
Competition (biology)
Competition is an interaction between organisms or species, in which the fitness of one is lowered by the presence of another. Limited supply of at least one resource used by both is required. Competition both within and between species is an important topic in ecology, especially community ecology...
in marine environments.