''Hirticlavula'' is a fungal

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

in the family

Clavariaceae The Clavariaceae are a family of fungi in the order Agaricales. Originally the family contained most of the clavarioid fungi (club and coral fungi), but in its current sense is more restricted, albeit with a greater diversity of basidiocarp (fru ...

. It contains a

single Single may refer to: Arts, entertainment, and media * Single (music), a song release Songs * "Single" (Natasha Bedingfield song), 2004 * "Single" (New Kids on the Block and Ne-Yo song), 2008 * "Single" (William Wei song), 2016 * "Single", by ...

described species, ''Hirticlavula elegans''. Formally described in 2014, the fungus has been collected from Norway and Denmark. ''H. elegans'' produces white

fruit bodies The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...

up to in height. Each fruit body contains a fertile head atop a hairy stem. The fruit bodies grow directly from dead bark or wood, where they feed as saprotrophs. Both morphological and ecological details are distinctive when compared to other clavarioid fungi.

Taxonomy

''Hirticlavula elegans'' was described based on collections dating back to 1995. It was provisionally reported in 2009 in the

proceedings In academia and librarianship, conference proceedings is a collection of academic papers published in the context of an academic conference or workshop. Conference proceedings typically contain the contributions made by researchers at the confere ...

of a 2008

conference A conference is a meeting of two or more experts to discuss and exchange opinions or new information about a particular topic. Conferences can be used as a form of group decision-making, although discussion, not always decisions, are the main p ...

, before being formally described in 2009 by Jens H. Petersen and Thomas Læssøe in an article in ''

Karstenia ''Karstenia'' is a genus of fungi in the order Rhytismatales. The relationship of this taxon to other taxa within the order (biology), order is unknown (''incertae sedis''), and it has not yet been placed with certainty into any family (biology), ...

'', coauthored with Marie L. Davey.Petersen, Davey, and Læssøe, p. 1. The specific name ''elegans'' is from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

meaning "elegant", and refers to how "pretty" the species's fruit bodies are. In Danish, the species has the

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

''hårkølle''.

Phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

suggests that within the Clavariaceae, ''Hirticlavula'' is a

sister A sister is a woman or a girl who shares one or more parents with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to refer to ...

to the

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

comprising ''

Clavaria ''Clavaria'' is a genus of fungi in the family Clavariaceae. Species of ''Clavaria'' produce basidiocarps (fruit bodies) that are either cylindrical to club-shaped or branched and coral-like. They are often grouped with similar-looking species f ...

'', '' Camarophyllopsis'' and '' Hodophilus''.Petersen, Davey, and Læssøe, p. 2.

Description

''Hirticlavula elegans'' produces white

from 800 to 1100

micrometres The micrometre (American and British English spelling differences#-re, -er, international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American and British English spelling differences# ...

(μm) in height. The robust and fertile head measures from 230 to 260 by 90 to 200 μm, while the hairy stem measures between 600 and 800 by 40 to 60 μm. The fruit bodies mostly retain their shape when dried, but do develop a

cream Cream is a dairy product composed of the higher-fat layer skimmed from the top of milk before homogenization. In un-homogenized milk, the fat, which is less dense, eventually rises to the top. In the industrial production of cream, this process ...

tinge. The fruit bodies do not emerge from a

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 favo ...

, but instead grow directly from the substrate.Petersen, Davey, and Læssøe, p. 4. The

basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly-c ...

are cyanophilous, meaning that the cell walls will readily absorb

methyl blue Methyl blue is a chemical compound with the molecular formula C37H27N3Na2O9S3. It is used as a stain in histology, and stains collagen blue in tissue sections. It can be used in some differential staining techniques such as Mallory's connect ...

stain. They measure 14 to 22 by 3.5 to 5 μm, and each sport four "curved and remarkably thin"

sterigmata In biology, a sterigma (pl. sterigmata) is a small supporting structure. It commonly refers to an extension of the basidium (the spore-bearing cells) consisting of a basal filamentous part and a slender projection which carries a spore at the ti ...

. The sterigmata are 4–5 μm in length. The smooth, broadly

ellipsoid An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...

spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

measure 4.5 to 6.5 by 3–4.2 μm. They are

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

, and either cyanophilous or containing cyanophilous particles. They contain no prominent crystals, and are topped by a 0.8 μm-long apiculus (the section that connects to the sterigmatum). The

hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

lack

clamp connections A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of Basidiomycetes fungi. It is created to ensure that each cell, or segment of hypha separated by septa (cross walls), rece ...

, and the hyphal structure is monomitic, meaning that only generative hyphae are present. In the stem, the 1–2 μm-wide hyphae run parallel to one another, but are less regular towards the base. The hairs on the stem are straight and point away from the substrate, emerging from the stems at oblique angles. They are 150 to 250 μm in length; at the base, they are 1.5 to 2.5 μm in width, while at the rounded to club-shaped tips, they are 3 to 4.5 μm in width. The hairs do not branch, have moderately thick

walls Walls may refer to: *The plural of wall, a structure * Walls (surname), a list of notable people with the surname Places * Walls, Louisiana, United States *Walls, Mississippi, United States * Walls, Ontario, neighborhood in Perry, Ontario, C ...

and are somewhat

septate In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatr ...

. Individual cells in the hairs measure 10 to 30 μm in length. It is unknown whether the fruit bodies are

edible An edible item is any item that is safe for humans to eat. "Edible" is differentiated from "eatable" because it does not indicate how an item tastes, only whether it is fit to be eaten. Nonpoisonous items found in nature – such as some mushroo ...

, but they are unlikely to be of interest to

mushroom hunters Mushroom hunting, mushrooming, mushroom picking, mushroom foraging, and similar terms describe the activity of gathering mushrooms in the wild, typically for culinary use. This practice is popular throughout most of Europe, Australia, Japan, ...

due to the small size.

Similar species

''Hirticlavula elegans'' fruit bodies are highly distinctive. The characteristic hairy stems are very different from those of any other species in the Clavariaceae. Hairy stems are seen among more distant relatives, including members of ''

Typhula ''Typhula'' is a genus of clavarioid fungi in the order Agaricales. Species of ''Typhula'' are saprotrophic, mostly decomposing leaves, twigs, and herbaceous material. Basidiocarps (fruit bodies) are club-shaped or narrowly cylindrical and are ...

'', '' Pistillina'' and ''

Pterula ''Pterula'' is a genus of fungi in the '' Pterulaceae'' family. The genus has a widespread distribution, especially in tropical regions, and contains about 50 species. One such species, ''Pterula sp. 82168'', has yielded potential antifungal anti ...

''. However, the hairs of ''H. elegans'' are specialised structures containing numerous cells, while the more irregular hairs on the stems of the other species are merely branched hyphae. In addition, the hairs on the ''H. elegans'' stems thicken at the furthest point from the stem, while any hairs on the stems of other known species of clavarioid fungi thin at the end.Petersen, Davey, and Læssøe, p. 4, 7.

Distribution and ecology

''Hirticlavula elegans'' is known from Denmark and Norway. The fruit bodies grow directly from the wood or, more usually, the bark of

hardwoods Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from ...

. Identified substrates include

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

willow Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...

hazel The hazel (''Corylus'') is a genus of deciduous trees and large shrubs native to the temperate Northern Hemisphere. The genus is usually placed in the birch family Betulaceae,Germplasmgobills Information Network''Corylus''Rushforth, K. (1999). ...

s and possibly

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 ...

es. The ecology of the species is distinctive; while other members of the Clavariaceae are biotrophic (feeding upon living plant matter), ''H. elegans'' grows on dead plant matter as a

saprotroph Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi (f ...

. The species fruits from May to October, longer than the fruiting of any other very small clavarioid fungi known to the describing authors.Petersen, Davey, and Læssøe, p. 7.

References

Cited texts