Inocybe cookei
Encyclopedia
Inocybe cookei, commonly known
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...

 as the straw fibrecap, is a species of 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...

 in the Inocybaceae
Inocybaceae
The Inocybaceae are a family of fungi in the Agaricales order. According to a 2008 estimate, the family contains 13 genera and 821 species. Members of this family have a widespread distribution in tropical and temperate areas.-Taxonomy:...

 family. It was first described in 1892 by Giacomo Bresadola
Giacomo Bresadola
Giacomo Bresadola 14 February 1847 – Trento 9 June 1929) was an eminent Italian mycologist. Fungi he named include the deadly Lepiota helveola and Inocybe patouillardii, though the latter is now known as Inocybe erubescens as this latter description predated Bresadola's by a year...

, and is named in honour of Mordecai Cubitt Cooke
Mordecai Cubitt Cooke
Mordecai Cubitt Cooke was an English botanist and mycologist.Cooke came from a mercantile family in Horning, Norfolk, and worked as an apprentice to a fabric merchant before becoming a clerk in a law firm, but his chief interest was in botany. He founded the Society of Amateur Botanists in 1862...

. The species can be found in Europe, Asia and North America. It produces small mushrooms of an ochre
Ochre
Ochre is the term for both a golden-yellow or light yellow brown color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues...

 colour, with a prominent 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...

, fibres on the 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 a distinctive bulb at the base of 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...

. It grows from soil in mixed woodland, and is encountered in summer and autumn, though is not common. Ecologically, it feeds through use of ectomycorrhiza. Inocybe cookei has been described as both toxic
Mushroom poisoning
Mushroom poisoning refers to harmful effects from ingestion of toxic substances present in a mushroom. These symptoms can vary from slight gastrointestinal discomfort to death. The toxins present are secondary metabolites produced in specific biochemical pathways in the fungal cells...

 and non-toxic, but either way, is not advised for consumption.

Taxonomy and naming

Inocybe cookei was first described by Giacomo Bresadola
Giacomo Bresadola
Giacomo Bresadola 14 February 1847 – Trento 9 June 1929) was an eminent Italian mycologist. Fungi he named include the deadly Lepiota helveola and Inocybe patouillardii, though the latter is now known as Inocybe erubescens as this latter description predated Bresadola's by a year...

 in 1892; the specific epithet cookei honours the British mycologist Mordecai Cubitt Cooke
Mordecai Cubitt Cooke
Mordecai Cubitt Cooke was an English botanist and mycologist.Cooke came from a mercantile family in Horning, Norfolk, and worked as an apprentice to a fabric merchant before becoming a clerk in a law firm, but his chief interest was in botany. He founded the Society of Amateur Botanists in 1862...

. Mycologists J. Stangl and J. Veselský described Inocybe kuthanii in 1979, which was later described as a variety of Inocybe cookei (Inocybe cookei var. kuthanii) by Thom Kuyper in 1986, but MycoBank
MycoBank
MycoBank is an online database, documenting new mycological names and combinations, eventually combined with descriptions and illustrations. It is run by the Centraalbureau voor Schimmelcultures fungal biodiversity center in Utrecht....

 now lists both names as synonyms
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...

 of I. cookei. The mushroom is commonly known
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...

 as the straw fibrecap.

Within Inocybe
Inocybe
Inocybe is a large, complex genus of mushrooms. Members of Inocybe are mycorrhizal, and some evidence shows that the high degree of speciation in the genus is due to adaptation to different trees and perhaps even local environments.-Description:...

, it is placed within the subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...

 Inosperma, and was previously categorised within the section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...

 Rimosae. However, phylogenetic analysis has shown that section Rimosae as formerly defined does not form a monophyletic group (that is, descended from a single exclusive ancestor), and former Rimosae species are better grouped into two clades
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...

, Maculata and Rimosae. Phylogenetic analysis has placed the species in the clade Maculata. Other species joining I. cookei in the Maculata clade include I. maculata
Inocybe maculata
Inocybe maculata, commonly known as the frosty fibrecap, is a species of mushroom in the Inocybaceae family. First described by Jean Louis Émile Boudier in 1885, I. maculata can be found throughout Europe, Asia and North America. It is a medium-sized brown mushroom with a fibrous, brown cap with...

, I. quietiodor, I. rhodiola, I. adaequata, and I. erubescens.

Description

Inocybe cookei has a conical or bell-shaped 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...

 of between 2 and 5 cm (0.78740157480315 and 2 in) in diametre. As the mushrooms age, the cap becomes flatter, and 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...

 becomes prominent. The margin of the cap frequently cracks towards the centre. The cap is an ochre
Ochre
Ochre is the term for both a golden-yellow or light yellow brown color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues...

 colour, and the upper surface is covered in long fibres. The silky fibres thickly cover the cap, starting and the centre and extending to the cap's margin. The species has a whitish or ochre 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...

 of 30 to 60 mm (1.2 to 2.4 in) in height by 4 to 8 mm (0.15748031496063 to 0.31496062992126 in) in thickness. There is a distinctive marginate bulb at the base of the stem, and no ring
Annulus (mycology)
An annulus is the ring like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like...

. 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 white, becoming yellow with age. Inocybe cookei mushrooms have closely packed adnexed gills (gills that are attached to the stem only on part of their depth). Gills on young mushrooms are whitish, then become a grey-tinged pale ochre before becoming cinnamon
Cinnamon
Cinnamon is a spice obtained from the inner bark of several trees from the genus Cinnamomum that is used in both sweet and savoury foods...

 yellow.

Microscopic features

Inocybe cookei leaves a snuff
Snuff
Snuff is a product made from ground or pulverised tobacco leaves. It is an example of smokeless tobacco. It originated in the Americas and was in common use in Europe by the 17th century...

-brown spore print
Spore print
thumb|300px|right|Making a spore print of the mushroom Volvariella volvacea shown in composite: mushroom cap laid on white and dark paper; cap removed after 24 hours showing pinkish-tan spore print...

. The spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

s themselves are bean
Bean
Bean is a common name for large plant seeds of several genera of the family Fabaceae used for human food or animal feed....

-shaped, measuring from 5.5 um by 4 um. The walls of the spores (which are around 0.5 um thick) can be smooth or slightly wrinkled, and there is a distinct depression just above the hilum (the scar where the spore was once attached to the basidium
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...

). The basidia are four-spored, and the thin-walled, gill-edge cheilocystidia are pear-shaped.

Similar species

The species can be differentiated from the similar I. praetervisa
Inocybe praetervisa
Inocybe praetervisa is a small, yellow and brown mushroom in the Inocybaceae family, distinguished from other members of the genus by its unusual spores and bulb...

by its spores; the latter "has irregular, lumpy spores". Inocybe rimosa, the split fibrecap, is also similar in appearance; the rarer I. cookei can be differentiated by the smell of honey and the marginate bulb. The colouration, as well as the thick stem with a bulb, are features shared by two other species of Inocybe; I. mixtilis and I. cryptocystis. Another fragrant Inocybe is I. pyriodora, which has an odor resembling cinnamon, or ripe pears in mature specimens; unlike I. cookei, it lacks a bulb at the base of its stem, and bruises a reddish colour when handled or with age.

Distribution and habitat

Inocybe cookei is an occasional to frequent mushroom, found growing in mixed woodland on the ground. It is ectomycorrhizal, and grows from summer to late autumn, solitarily or in "trooping groups". It has been recorded in Europe, Russia, China, Mexico, and the United States.

Toxicity and edibility

Inocybe cookei has been described as both poisonous
Mushroom poisoning
Mushroom poisoning refers to harmful effects from ingestion of toxic substances present in a mushroom. These symptoms can vary from slight gastrointestinal discomfort to death. The toxins present are secondary metabolites produced in specific biochemical pathways in the fungal cells...

 (due to the presence of muscarine
Muscarine
Muscarine, L--muscarine, or muscarin is a natural product found in certain mushrooms, particularly in Inocybe and Clitocybe species, such as the deadly C. dealbata. Mushrooms in the genera Entoloma and Mycena have also been found to contain levels of muscarine which can be dangerous if ingested...

 compounds) and non-toxic. Consumption of mushrooms containing muscarine compounds could lead to a number of physiological effects, including: excess salivation, lacrimation, uncontrolled urination
Urination
Urination, also known as micturition, voiding, peeing, weeing, pissing, and more rarely, emiction, is the ejection of urine from the urinary bladder through the urethra to the outside of the body. In healthy humans the process of urination is under voluntary control...

 or defecation
Defecation
Defecation is the final act of digestion by which organisms eliminate solid, semisolid or liquid waste material from the digestive tract via the anus. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum...

, gastrointestinal problems and emesis (vomiting); this array of symptoms may also be known by the acronym SLUDGE. Other potential effects include a drop in blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...

, sweating
Sweating
Perspiration is the production of a fluid consisting primarily of water as well as various dissolved solids , that is excreted by the sweat glands in the skin of mammals...

 and death due to respiratory failure
Respiratory failure
The term respiratory failure, in medicine, is used to describe inadequate gas exchange by the respiratory system, with the result that arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial...

. The flesh of the mushroom has a mild taste and a slight smell of honey. Regardless of its actual toxicity or edibility, it is considered "best avoided".
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