Dendrocollybia
Encyclopedia
Dendrocollybia is a genus
of fungus
in the Tricholomataceae
family of the Agaricales
order. It is a monotypic
genus, containing the single species Dendrocollybia racemosa, commonly
known as the branched Collybia or the branched shanklet. The somewhat rare species is found in the Northern Hemisphere
, including the Pacific Northwest
region of western North America, and Europe, where it is included in several Regional Red List
s. It usually grows on the decaying fruit bodies
of other agaric
s—such as Lactarius
and Russula
—although the host
mushrooms may be decayed to the point of being difficult to recognize.
Dendrocollybia racemosa fruit bodies have small pale grayish-white or grayish-brown caps
up to 1 cm (0.393700787401575 in) wide, and thin stems
up to 6 cm (2.4 in) long. The species is characterized by its unusual stem, which is covered with short lateral branches. The branches often produce spherical slimeheads of translucent conidiophores
on their swollen tips. The conidiophores produce conidia (asexual spore
s) by mitosis
. Because the fungus can rely on either sexual
or asexual
modes of reproduction, fruit bodies sometimes have reduced or even missing caps. The unusual stems originate from black pea-sized structures called sclerotia
. The anamorphic
form of the fungus, known as Tilachlidiopsis
racemosa, is missing the sexual stage of its life cycle
. It is able to reproduce at relatively low temperatures, an adaptation believed to improve its ability to grow quickly and fruit on decomposing mushrooms.
was considered to be one of four species of Collybia
, a genus which had itself been redefined and reduced in 1997, when most of its species were transferred to Gymnopus
and Rhodocollybia
. C. racemosa was originally described and named Agaricus racemosus by Christian Hendrik Persoon
in 1797, and sanctioned
under that name by Elias Magnus Fries
in 1821. In his Systema Mycologicum
, Fries classified it in his "tribe" Collybia along with all other similar small, white-spored species with a convex cap and a fragile stem. In 1873 Lucien Quélet
raised Fries' tribe Collybia to generic rank. Samuel Frederick Gray
called the species Mycena racemosa in his 1821 Natural Arrangement of British Plants; both this name and Joanne Lennox's 1979 Microcollybia racemosa are considered synonyms.
Rolf Singer
's fourth edition (1986) of his comprehensive Agaricales in Modern Taxonomy included Collybia racemosa in section Collybia, in addition to the three species that currently comprise the genus Collybia: C. tuberosa
, C. cirrhata
and C. cookei
. A phylogenetic analysis of the internal transcribed spacer
sequences of ribosomal DNA
by Karen Hughes and colleagues showed that C. tuberosa, C. cirrhata and C. cookei form a monophyletic group within a larger Lyophyllum–Tricholoma–Collybia clade
that includes several species of Lyophyllum
, Tricholoma, Lepista
, Hypsizygus
and the species C. racemosa. Hughes and colleagues were not able to identify a clade that included all four species of Collybia. Restriction fragment length polymorphism
analysis of the ribosomal DNA from the four species corroborated the results obtained from phylogenetic analysis. Based on these results, as well as differences in characteristics such as the presence of unique stem projections, fruit body pigment
ation, and macrochemical reactions
, they circumscribed the new genus Dendrocollybia to contain C. racemosa.
The fungus is commonly
known as the branched Collybia, or the branched shanklet; Samuel Gray referred to it as the "racemelike high-stool". The genus name Dendrocollybia is a combination of the Ancient Greek
words dendro-, meaning "tree", and collybia, meaning "small coin". The specific epithet racemosa is from the Latin
word racemus—"a cluster of grapes".
of Dendrocollybia racemosa is typically between 3 to 10 mm (0.118110236220472 to 0.393700787401575 in) in diameter, and depending on its stage of development, may be conic to convex, or in maturity, somewhat flattened with a slight rounded central elevation (an umbo
). The cap surface is dry and opaque, with a silky texture; its color in the center is fuscous (a dusky brownish-gray color), but the color fades uniformly towards the margin. The margin is usually curved toward the gills initially; as the fruit body matures the edge may roll out somewhat, but it also has a tendency to fray or split with age. There may be shallow grooves on the cap that correspond to the position of the gills underneath, which may give the cap edge a crenate (scalloped) appearance. The flesh
is very thin (less than 1 mm thick) and fragile, lacking in color, and has no distinctive odor or taste. The gills are relatively broad, narrowly attached to the stem (adnexed), spaced closely together, and colored gray to grayish-tan
, somewhat darker than the cap. There are additional gills, called lamellulae, that do not extend all the way to the stem; they are interspersed between the gills and arranged in up to three series (tiers) of equal length. Occasionally, the fungus produces stems with aborted caps, or with the caps missing entirely.
The stem
is 4 to 6 cm (1.6 to 2.4 in) long by 1 mm thick, roughly equal in width throughout, and tapers to a long "root" which terminates in a dull black, roughly spherical sclerotium
. The stem may be buried deeply in its substrate
. The stem surface is roughly the same color as the cap, with a fine whitish powder on the upper surface. In the lower portion, the stem is brownish, and has fine grooves that run lengthwise up and down the surface. The lower half is covered with irregularly arranged short branch-like protuberances at right angles to the stem that measure 2–3 by 0.5 mm. These projections are cylindrical and tapering, with ends that are covered with a slime head of conidia
(fungal spores produced asexually
). D. racemosa is the only mushroom species known that forms conidia on side branches of the stem. The sclerotium from which the stem arises is watery grayish and homogeneous in cross section (not divided into internal chambers), with a thin dull black outer coat, and measures 3 to 6 mm (0.118110236220472 to 0.236220472440945 in) in diameter. American mycologist Alexander H. Smith
cautioned that novice collectors will typically miss the sclerotium the first time they find the species. The edibility
of D. racemosa is unknown, but as David Arora
says, the fruit bodies are "much too puny and rare to be of value."
s are narrowly ellipsoid to ovoid, thin-walled, hyaline
(translucent), with dimensions of 4–5.5 by 2–3 µm
. When stained with Melzer's reagent
, the spores turn a light blue color. The basidia (the spore-bearing cells) are four-spored, measure 16–20 by 3.5–4 µm, and taper gradually towards the base. Cystidia are not differentiated in this species. The cap surface is made of a cuticle
of radial, somewhat agglutinated, rather coarse hypha
e that differ chiefly in size from the underlying tissue—initially 1–3 µm in diameter, becoming 5–7 µm wide in the underlying tissue. The hyphae are clamped
, and encrusted with shallow irregularly shaped masses that are most conspicuous in the surface cells. The gill tissue is made of hyphae that project downward from the cap and arranged in a subparallel fashion, meaning that the hyphae are mostly parallel to one another and are slightly intertwined. The hyphae are clamped, with a narrow, branched compact subhymenium (a narrow zone of small, short hyphae immediately beneath the hymenium) composed of hyphae 2–3 µm in diameter. The conidia are 8.5–12 by 4–5 µm, peanut-shaped, non-amyloid
(not changing color when stained with Melzer's reagent), clamped, and produced by fragmentation of the coarse mycelium
. Clamp connection
s are present in the hyphae. Asexual spores are 10.0–15.5 by 3–4 µm, ellipsoid to oblong, non-amyloid, and contain granular
contents. The grayish color of the fruit bodies is caused by encrusted pigments (crystalline aggregates of pigment molecules, possibly melanin
) that occur throughout the tissue of the stem and cap, including the gills; these pigments are absent in Collybia species.
, including aniline
, alpha-napthol
, guaiacol
, sulfoformol, phenol
, and phenol-aniline.
The cortex (outer tissue layer) of the sclerotium can be used as a diagnostic character to distinguish between D. racemosa and small white specimens of Collybia. The hyphae of the cortex of D. racemosa are "markedly angular", in comparison with C. cookei (rounded hyphae) and C. tuberosa (elongated hyphae). The cortical layer in D. racemosa has an arrangement that is known as textura epidermoidea—with the hyphae arranged like a jigsaw puzzle. Heavy deposits of dark reddish-brown pigment are evident throughout the cortical tissue in or on the walls and the tips of hyphae. The remaining Collybia species, C. cirrhata, does not form sclerotia.
are those that seem to lack a sexual stage in their life cycle
, and typically reproduce by the process of mitosis
in conidia
. In some cases, the sexual stage—or teleomorph
stage—is later identified, and a teleomorph-anamorph relationship is established between the species. The International Code of Botanical Nomenclature permits the recognition of two (or more) names for one and the same organism, one based on the teleomorph, the other(s) restricted to the anamorph. Tilachlidiopsis
racemosa (formerly known as Sclerostilbum septentrionale, described by Alfred Povah in 1932) was shown to be the anamorphic form of Dendrocollybia racemosa. The synnemata (reproductive structures made of compact groups of erect conidiophores) produced by T. racemosa always grow on the stem of Dendrocollybia racemosa. The anamorph has an unusually low optimum growth temperature, between 12 and 18 °C (53.6 and 64.4 °F), within a larger growth range of 3 and 22 °C (37.4 and 71.6 °F). It is thought that this is an adaptation which allows the mycelium to grow quickly and enhance its chances of fruiting on agaric mushrooms, which are generally short-lived.
s, often suspected to be Lactarius
or Russula
, although the hosts' identity are often unclear due to an advanced state of decay. A 2006 study used molecular analysis to confirm Russula crassotunicata as a host for D. racemosa. This Russula has a long and persistent decay period, and, in the Pacific Northwest
region of the United States where the study was conducted, provides a "nearly year-round substrate for mycosaprobic species". Dendrocollybia is one of four agaric genera obligately associated with growth on the fruit bodies of other fungi, the others being Squamanita
, Asterophora
, and Collybia. Dendrocollybia is also found less commonly in deep coniferous duff
, in groups or small clusters. The fungus can form sclerotia in the mummified host fruit bodies, and may also develop directly from their sclerotia in soil. The fungus is widely distributed in temperate
regions of the Northern Hemisphere
, but rarely collected "probably due to its small size, camouflage color, and tendency to be immersed in its substrate." In North America, where the distribution is restricted to the Pacific Northwest, fruit bodies are found in the late summer to autumn, often after a heavy fruiting period for other mushrooms is over. In Europe, it is known from the United Kingdom, Scandinavia
, and Belgium. Dendrocollybia racemosa is in the Danish, Norwegian, and British Red List
s.
The saprobic behaviors of Collybia and Dendrocollybia are slightly different. In the autumn, fruit bodies of C. cirrhata, C. cookei and C. tuberosa, can be found on blackened, leathery, mummified fruit bodies of their hosts. Sometimes, these species appear to be growing in the soil (or from their sclerotium in soil or moss
), but usually not in huge clusters. In these cases it is assumed that the hosts are remnants of fruit bodies from a previous season. In all observed cases of D. racemosa, however, the hosts have not been readily observed, suggesting that rapid digestion of the host (rather than mummification) may have taken place. Hughes and colleagues suggest that this may indicate the presence of a different enzymatic system, and a differing ability to compete with other fungi or bacteria.
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...
of fungus
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 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 of the 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...
order. It is a monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
genus, containing the single species Dendrocollybia racemosa, commonly
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...
known as the branched Collybia or the branched shanklet. The somewhat rare species is found in the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
, including the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
region of western North America, and Europe, where it is included in several 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. It usually grows on the decaying 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...
of other agaric
Agaric
An agaric is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe , with lamellae on the underside of the pileus. "Agaric" can also refer to a basidiomycete species characterized by an agaric-type fruiting body...
s—such as Lactarius
Lactarius
Lactarius is a genus of mushroom-producing fungi. The genus, collectively known commonly as milk-caps, are characterized by the fact that they exude a milky fluid if cut or damaged...
and Russula
Russula
Around 750 worldwide species of mycorrhizal mushrooms compose the genus Russula. They are typically common, fairly large, and brightly colored - making them one of the most recognizable genera among mycologists and mushroom collectors...
—although the host
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
mushrooms may be decayed to the point of being difficult to recognize.
Dendrocollybia racemosa fruit bodies have small pale grayish-white or grayish-brown caps
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...
up to 1 cm (0.393700787401575 in) wide, and thin stems
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...
up to 6 cm (2.4 in) long. The species is characterized by its unusual stem, which is covered with short lateral branches. The branches often produce spherical slimeheads of translucent conidiophores
Conidium
Conidia, sometimes termed conidiospores, are asexual, non-motile spores of a fungus and are named after the greek word for dust, konia. They are also called mitospores due to the way they are generated through the cellular process of mitosis...
on their swollen tips. The conidiophores produce conidia (asexual 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) by mitosis
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...
. Because the fungus can rely on either sexual
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
or asexual
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
modes of reproduction, fruit bodies sometimes have reduced or even missing caps. The unusual stems originate from black pea-sized structures called sclerotia
Sclerotium
A sclerotium is a compact mass of hardened fungal mycelium containing food reserves. One role of sclerotia is to survive environmental extremes. In some higher fungi such as ergot, sclerotia become detached and remain dormant until a favorable opportunity for growth. Other fungi that produce...
. The anamorphic
Teleomorph, anamorph and holomorph
The terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota.*Teleomorph: the sexual reproductive stage , typically a fruiting body....
form of the fungus, known as Tilachlidiopsis
Tilachlidiopsis
Tilachlidiopsis is a genus of fungi in the Tricholomataceae family.-External links:* at Index Fungorum...
racemosa, is missing the sexual stage 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...
. It is able to reproduce at relatively low temperatures, an adaptation believed to improve its ability to grow quickly and fruit on decomposing mushrooms.
Taxonomy and phylogeny
The genus Dendrocollybia was first described in 2001, to accommodate the species previously known as Collybia racemosa. Before then, the so-named taxonTaxon
|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...
was considered to be one of four species of Collybia
Collybia
Collybia is a genus of mushrooms in the Tricholomataceae family. The genus has a widespread but rare distribution in north temperate areas, and contains three species that grow on the decomposing remains of other mushrooms....
, a genus which had itself been redefined and reduced in 1997, when most of its species were transferred to Gymnopus
Gymnopus
Gymnopus is a genus of fungus in the Marasmiaceae family. The genus has a widespread distribution and contains about 300 species.-Representative species:*Gymnopus dryophilus*Gymnopus fusipes*Gymnopus peronatus*Gymnopus semihirtipes...
and Rhodocollybia
Rhodocollybia
Rhodocollybia is a genus of Basidiomycete mushroom. Species in this genus, formerly classified as a subgenus in Collybia, have fairly large caps , and have a pinkish-tinted spore print...
. C. racemosa was originally described and named Agaricus racemosus by Christian Hendrik Persoon
Christian Hendrik Persoon
Christiaan Hendrik Persoon was a mycologist who made additions to Linnaeus' mushroom taxonomy.-Early life:...
in 1797, and 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:...
under that name by Elias Magnus Fries
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
in 1821. In his Systema Mycologicum
Systema Mycologicum
Systema Mycologicum is a systematic classification of fungi drawn up in 1821 by the Swedish mycologist and botanist Elias Fries. It took 11 years to complete....
, Fries classified it in his "tribe" Collybia along with all other similar small, white-spored species with a convex cap and a fragile stem. In 1873 Lucien Quélet
Lucien Quélet
thumb|Lucien QuéletLucien Quélet was a French mycologist and naturalist who discovered several species and was the founder of the Société mycologique de France, a society devoted to mycological studies....
raised Fries' tribe Collybia to generic rank. 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 the species Mycena racemosa in his 1821 Natural Arrangement of British Plants; both this name and Joanne Lennox's 1979 Microcollybia racemosa are considered synonyms.
Rolf Singer
Rolf Singer
Rolf Singer was a German-born mycologist and one of the most important taxonomists of gilled mushrooms in the 20th century....
's fourth edition (1986) of his comprehensive Agaricales in Modern Taxonomy included Collybia racemosa in section Collybia, in addition to the three species that currently comprise the genus Collybia: C. tuberosa
Collybia tuberosa
Collybia tuberosa, commonly known as the lentil shanklet or the appleseed coincap, is an inedible species of fungus in the Tricholomataceae family, and the type species of the genus Collybia. Like the two other members of its genus, it lives on the decomposing remains of other fleshy mushrooms...
, C. cirrhata
Collybia cirrhata
Collybia cirrhata is a species of fungus in the Tricholomataceae family of the Agaricales order . The species was first described in the scientific literature in 1786, but not validly named until 1803. Found in Europe, Northern Eurasia, and North America, it is known from temperate, boreal, and...
and C. cookei
Collybia cookei
Collybia cookei is a species of fungus in the Tricholomataceae family, and one of three species in the genus Collybia. It is known from Europe, Asia, and North America...
. A phylogenetic analysis of the internal transcribed spacer
Internal transcribed spacer
ITS refers to a piece of non-functional RNA situated between structural ribosomal RNAs on a common precursor transcript. Read from 5' to 3', this polycistronic rRNA precursor transcript contains the 5' external transcribed sequence , 18S rRNA, ITS1, 5.8S rRNA, ITS2, 28S rRNA and finally the 3'ETS...
sequences 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...
by Karen Hughes and colleagues showed that C. tuberosa, C. cirrhata and C. cookei form a monophyletic group within a larger Lyophyllum–Tricholoma–Collybia clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
that includes several species of Lyophyllum
Lyophyllum
Lyophyllum is a genus of about 40 species of fungi, widespread in north temperate regions.-Species:*Lyophyllum connatum*Lyophyllum decastes*Lyophyllum eustygium*Lyophyllum favrei*Lyophyllum fumosum*Lyophyllum gangraenosum...
, Tricholoma, Lepista
Lepista
Lepista is a deprecated genus of mushrooms, formerly grouped in the large genus Tricholoma and more recently found to be a synonym of Clitocybe. However, Clitocybe itself appears polyphyletic and may have to be split...
, Hypsizygus
Hypsizygus
Hypsizygus is a small genus of fungi that are widely distributed in north temperate regions. The genus was circumscribed by Rolf Singer in 1947....
and the species C. racemosa. Hughes and colleagues were not able to identify a clade that included all four species of Collybia. Restriction fragment length polymorphism
Restriction fragment length polymorphism
In molecular biology, restriction fragment length polymorphism, or RFLP , is a technique that exploits variations in homologous DNA sequences. It refers to a difference between samples of homologous DNA molecules that come from differing locations of restriction enzyme sites, and to a related...
analysis of the ribosomal DNA from the four species corroborated the results obtained from phylogenetic analysis. Based on these results, as well as differences in characteristics such as the presence of unique stem projections, fruit body pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
ation, and macrochemical reactions
Chemical tests in mushroom identification
Chemical tests in mushroom identification are methods that aid in determining the variety of some fungi. The most useful tests are Melzer's reagent and potassium hydroxide.- Ammonia :Household ammonia can be used. A couple of drops are placed on the flesh...
, they circumscribed the new genus Dendrocollybia to contain C. racemosa.
The fungus is commonly
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...
known as the branched Collybia, or the branched shanklet; Samuel Gray referred to it as the "racemelike high-stool". The genus name Dendrocollybia is a combination of the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
words dendro-, meaning "tree", and collybia, meaning "small coin". The specific epithet racemosa is from the 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...
word racemus—"a cluster of grapes".
Description
The capPileus (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...
of Dendrocollybia racemosa is typically between 3 to 10 mm (0.118110236220472 to 0.393700787401575 in) in diameter, and depending on its stage of development, may be conic to convex, or in maturity, somewhat flattened with a slight rounded central elevation (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...
). The cap surface is dry and opaque, with a silky texture; its color in the center is fuscous (a dusky brownish-gray color), but the color fades uniformly towards the margin. The margin is usually curved toward the gills initially; as the fruit body matures the edge may roll out somewhat, but it also has a tendency to fray or split with age. There may be shallow grooves on the cap that correspond to the position of the gills underneath, which may give the cap edge a crenate (scalloped) appearance. The flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....
is very thin (less than 1 mm thick) and fragile, lacking in color, and has no distinctive odor or taste. The gills are relatively broad, narrowly attached to the stem (adnexed), spaced closely together, and colored gray to grayish-tan
Tan (color)
Tan is a pale whiteish, tawny shade of white. The name is derived from tannum used in the tanning of leather.The first recorded use of tan as a shade name in English was in the year 1590....
, somewhat darker than the cap. There are additional gills, called lamellulae, that do not extend all the way to the stem; they are interspersed between the gills and arranged in up to three series (tiers) of equal length. Occasionally, the fungus produces stems with aborted caps, or with the caps missing entirely.
The 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...
is 4 to 6 cm (1.6 to 2.4 in) long by 1 mm thick, roughly equal in width throughout, and tapers to a long "root" which terminates in a dull black, roughly spherical sclerotium
Sclerotium
A sclerotium is a compact mass of hardened fungal mycelium containing food reserves. One role of sclerotia is to survive environmental extremes. In some higher fungi such as ergot, sclerotia become detached and remain dormant until a favorable opportunity for growth. Other fungi that produce...
. The stem may be buried deeply in its 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...
. The stem surface is roughly the same color as the cap, with a fine whitish powder on the upper surface. In the lower portion, the stem is brownish, and has fine grooves that run lengthwise up and down the surface. The lower half is covered with irregularly arranged short branch-like protuberances at right angles to the stem that measure 2–3 by 0.5 mm. These projections are cylindrical and tapering, with ends that are covered with a slime head of conidia
Conidium
Conidia, sometimes termed conidiospores, are asexual, non-motile spores of a fungus and are named after the greek word for dust, konia. They are also called mitospores due to the way they are generated through the cellular process of mitosis...
(fungal spores produced asexually
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
). D. racemosa is the only mushroom species known that forms conidia on side branches of the stem. The sclerotium from which the stem arises is watery grayish and homogeneous in cross section (not divided into internal chambers), with a thin dull black outer coat, and measures 3 to 6 mm (0.118110236220472 to 0.236220472440945 in) in diameter. American mycologist Alexander H. Smith
Alexander H. Smith
Alexander Hanchett Smith was an American mycologist known for his extensive contributions to the taxonomy and phylogeny of the higher fungi, especially the agarics.-Early life:...
cautioned that novice collectors will typically miss the sclerotium the first time they find the species. The edibility
Edible mushroom
Edible mushrooms are the fleshy and edible fruiting bodies of several species of fungi. Mushrooms belong to the macrofungi, because their fruiting structures are large enough to be seen with the naked eye. They can appear either below ground or above ground where they may be picked by hand...
of D. racemosa is unknown, but as David Arora
David Arora
David Arora is an American mycologist, naturalist, and writer. He is the author of two popular books on mushroom identification, Mushrooms Demystified and All That the Rain Promises and More.......
says, the fruit bodies are "much too puny and rare to be of value."
Microscopic characteristics
The sporeSpore
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 are narrowly ellipsoid to ovoid, thin-walled, 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), with dimensions of 4–5.5 by 2–3 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...
. When stained with Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...
, the spores turn a light blue color. The basidia (the spore-bearing cells) are four-spored, measure 16–20 by 3.5–4 µm, and taper gradually towards the base. Cystidia are not differentiated in this species. The cap surface is made of a cuticle
Pileipellis
thumb|300px||right|The cuticle of some mushrooms, such as [[Russula mustelina]] shown here, can be peeled from the cap, and may be useful as an identification feature....
of radial, somewhat agglutinated, rather coarse 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 that differ chiefly in size from the underlying tissue—initially 1–3 µm in diameter, becoming 5–7 µm wide in the underlying tissue. The hyphae are clamped
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...
, and encrusted with shallow irregularly shaped masses that are most conspicuous in the surface cells. The gill tissue is made of hyphae that project downward from the cap and arranged in a subparallel fashion, meaning that the hyphae are mostly parallel to one another and are slightly intertwined. The hyphae are clamped, with a narrow, branched compact subhymenium (a narrow zone of small, short hyphae immediately beneath the hymenium) composed of hyphae 2–3 µm in diameter. The conidia are 8.5–12 by 4–5 µm, peanut-shaped, non-amyloid
Amyloid (mycology)
In mycology the term amyloid refers to a crude chemical test using iodine in either Melzer's reagent or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch gives a similar reaction, and that reaction for starch is also called an amyloid reaction...
(not changing color when stained with Melzer's reagent), clamped, and produced by fragmentation of the coarse 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...
. 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 are present in the hyphae. Asexual spores are 10.0–15.5 by 3–4 µm, ellipsoid to oblong, non-amyloid, and contain granular
Granule (cell biology)
In cell biology, a granule is a small particle. It can be any structure barely visible by light microscopy. The term is most often used to describe a secretory vesicle.-Leukocytes:...
contents. The grayish color of the fruit bodies is caused by encrusted pigments (crystalline aggregates of pigment molecules, possibly melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...
) that occur throughout the tissue of the stem and cap, including the gills; these pigments are absent in Collybia species.
Similar species
In contrast to the three species of Collybia, D. racemosa shows negligible reactivity to common chemical tests used in mushroom identificationChemical tests in mushroom identification
Chemical tests in mushroom identification are methods that aid in determining the variety of some fungi. The most useful tests are Melzer's reagent and potassium hydroxide.- Ammonia :Household ammonia can be used. A couple of drops are placed on the flesh...
, including aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
, alpha-napthol
1-Naphthol
1-Naphthol, or α-naphthol, is a colorless crystalline solid with the formula C10H7OH. It is an isomer of 2-naphthol differing by the location of the hydroxyl group on naphthalene. The naphthols are naphthalene homologues of phenol, with the hydroxyl group being more reactive than in the phenols....
, guaiacol
Guaiacol
Guaiacol is a naturally occurring organic compound with the formula C6H4. Although it is biosynthesized by a variety of organisms, this colorless aromatic oil is usually derived from guaiacum or wood creosote. Samples darken upon exposure to air and light. Guaiacol is present in wood smoke,...
, sulfoformol, phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...
, and phenol-aniline.
The cortex (outer tissue layer) of the sclerotium can be used as a diagnostic character to distinguish between D. racemosa and small white specimens of Collybia. The hyphae of the cortex of D. racemosa are "markedly angular", in comparison with C. cookei (rounded hyphae) and C. tuberosa (elongated hyphae). The cortical layer in D. racemosa has an arrangement that is known as textura epidermoidea—with the hyphae arranged like a jigsaw puzzle. Heavy deposits of dark reddish-brown pigment are evident throughout the cortical tissue in or on the walls and the tips of hyphae. The remaining Collybia species, C. cirrhata, does not form sclerotia.
Anamorph form
The anamorphic or imperfect fungiFungi imperfecti
The Fungi imperfecti or imperfect fungi, also known as Deuteromycota, are fungi which do not fit into the commonly established taxonomic classifications of fungi that are based on biological species concepts or morphological characteristics of sexual structures because their sexual form of...
are those that seem to lack a sexual stage in their 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...
, and typically reproduce by the process of mitosis
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...
in conidia
Conidium
Conidia, sometimes termed conidiospores, are asexual, non-motile spores of a fungus and are named after the greek word for dust, konia. They are also called mitospores due to the way they are generated through the cellular process of mitosis...
. In some cases, the sexual stage—or teleomorph
Teleomorph, anamorph and holomorph
The terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota.*Teleomorph: the sexual reproductive stage , typically a fruiting body....
stage—is later identified, and a teleomorph-anamorph relationship is established between the species. The International Code of Botanical Nomenclature permits the recognition of two (or more) names for one and the same organism, one based on the teleomorph, the other(s) restricted to the anamorph. Tilachlidiopsis
Tilachlidiopsis
Tilachlidiopsis is a genus of fungi in the Tricholomataceae family.-External links:* at Index Fungorum...
racemosa (formerly known as Sclerostilbum septentrionale, described by Alfred Povah in 1932) was shown to be the anamorphic form of Dendrocollybia racemosa. The synnemata (reproductive structures made of compact groups of erect conidiophores) produced by T. racemosa always grow on the stem of Dendrocollybia racemosa. The anamorph has an unusually low optimum growth temperature, between 12 and 18 °C (53.6 and 64.4 °F), within a larger growth range of 3 and 22 °C (37.4 and 71.6 °F). It is thought that this is an adaptation which allows the mycelium to grow quickly and enhance its chances of fruiting on agaric mushrooms, which are generally short-lived.
Habitat, distribution, and ecology
Dendrocollybia racemosa is a saprobic species, meaning it derives nutrients by breaking down dead or dying tissue. Its fruit bodies grow on the well-decayed remains of agaricAgaric
An agaric is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe , with lamellae on the underside of the pileus. "Agaric" can also refer to a basidiomycete species characterized by an agaric-type fruiting body...
s, often suspected to be Lactarius
Lactarius
Lactarius is a genus of mushroom-producing fungi. The genus, collectively known commonly as milk-caps, are characterized by the fact that they exude a milky fluid if cut or damaged...
or Russula
Russula
Around 750 worldwide species of mycorrhizal mushrooms compose the genus Russula. They are typically common, fairly large, and brightly colored - making them one of the most recognizable genera among mycologists and mushroom collectors...
, although the hosts' identity are often unclear due to an advanced state of decay. A 2006 study used molecular analysis to confirm Russula crassotunicata as a host for D. racemosa. This Russula has a long and persistent decay period, and, in the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
region of the United States where the study was conducted, provides a "nearly year-round substrate for mycosaprobic species". Dendrocollybia is one of four agaric genera obligately associated with growth on the fruit bodies of other fungi, the others being Squamanita
Squamanita
Squamanita is a genus of fungi in the Tricholomataceae family. The genus contains ten species that collectively have a widespread distribution....
, Asterophora
Asterophora
Asterophora is a genus of fungi that grow as parasites on mushrooms. The genus contains three species, which have a widespread distribution, especially in temperate areas.Asterophora species are characterized by the massive production of chlamydospores in their fruit bodies and by the production of...
, and Collybia. Dendrocollybia is also found less commonly in deep coniferous duff
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...
, in groups or small clusters. The fungus can form sclerotia in the mummified host fruit bodies, and may also develop directly from their sclerotia in soil. The fungus is widely distributed in temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
regions of the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
, but rarely collected "probably due to its small size, camouflage color, and tendency to be immersed in its substrate." In North America, where the distribution is restricted to the Pacific Northwest, fruit bodies are found in the late summer to autumn, often after a heavy fruiting period for other mushrooms is over. In Europe, it is known from the United Kingdom, Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
, and Belgium. Dendrocollybia racemosa is in the Danish, Norwegian, and British 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.
The saprobic behaviors of Collybia and Dendrocollybia are slightly different. In the autumn, fruit bodies of C. cirrhata, C. cookei and C. tuberosa, can be found on blackened, leathery, mummified fruit bodies of their hosts. Sometimes, these species appear to be growing in the soil (or from their sclerotium in soil or moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
), but usually not in huge clusters. In these cases it is assumed that the hosts are remnants of fruit bodies from a previous season. In all observed cases of D. racemosa, however, the hosts have not been readily observed, suggesting that rapid digestion of the host (rather than mummification) may have taken place. Hughes and colleagues suggest that this may indicate the presence of a different enzymatic system, and a differing ability to compete with other fungi or bacteria.
External links
- Fungi of Poland Several photographs
- National Botanic Garden of Belgium Photo of herbarium specimen