''Gerronema'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of over 50 fungi species that form

agaric An agaric () is a type of fungal fruiting body characterized by the presence of a pileus (cap) that is clearly differentiated from the stipe (stalk), with lamellae (gills) on the underside of the pileus. It is a type of mushroom (or toadstool) ...

fruit bodies. They are of small to medium size, with a centrally depressed cap. They are similar to '' Omphalina'' species. A

wood-decay fungus A wood-decay or xylophagous fungus is any species of fungus that digests moist wood, causing it to rot. Some species of wood-decay fungi attack dead wood, such as ''Serpula lacrymans'', and some, such as '' Armillaria'' (honey fungus), are par ...

, ''Gerronema'' has a primarily tropical distribution, occurring in Europe and eastern North America.

Taxonomy

The genus was circumscribed by American mycologist

Rolf Singer Rolf Singer (June 23, 1906 – January 18, 1994) was a German mycologist and Taxonomy (biology), taxonomist of gilled mushrooms (agarics). He wrote the book "The Agaricales in Modern Taxonomy (biology), Taxonomy". He fled to various countries d ...

in 1951.

Phylogeny

''Gerronema'' belongs to the informal 'hydropoid' clade, together with '' Hydropus'', '' Megacollybia'' and '' Clitocybula.'' In a phylogenetic study of ''Clitocybulas'', the hydropoid clade was found to contain 8 genera. In 2019, the hydropoid clade was moved to Porotheleaceae, removing ''Gerronema'' from

Marasmiaceae The Marasmiaceae are a family (biology), family of fungi in the order (biology), order Agaricales. Basidiocarps (fruit bodies) are most frequently agarics (gilled mushrooms), but occasionally cyphelloid (in the genus ''Cellypha''). According to a ...

. The same study also recognized ''Gerronema'' as

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

on the basis of previous taxonomic studies and divided it into seven clades, designated as ''Gerronema'' 1 to ''Gerronema'' 7.

Species

, ''

Index Fungorum ''Index Fungorum'' is an international project to index all formal names (scientific names) in the fungus kingdom. As of 2015, the project is based at the Royal Botanic Gardens, Kew, one of three partners along with Landcare Research and th ...

'' lists 55 species in ''Gerronema'': and a new combination was published in 2019. *'' G. aconquijense'' *'' G. albidum'' *'' G. albogriseolum'' *'' G. alutaceum'' *'' G. amabile'' *'' G. atrialba'' *'' G. baishanzuense'' *'' G. bethlehemicum'' *'' G. brunneum'' *'' G. bryogeton'' *'' G. calongei'' *'' G. candidum'' *'' G. chrysocarpum'' *'' G. chrysocraspedum'' *'' G. cinctum'' *'' G. citrinum'' *'' G. collybiomorphum'' *'' G. corticiphilum'' *'' G. costaricense'' *'' G. cyathiforme'' *'' G. daamsii'' *'' G. daguense'' *'' G. farinolens'' *'' G. fibula'' *'' G. flammeum'' *'' G. glutinipes'' *'' G. hungo'' *'' G. incarnatum'' *'' G. infumatum'' *'' G. josserandii'' *'' G. laccarioides'' *'' G. longipes'' *'' G. majus'' *'' G. mariae'' *'' G. microcarpum'' *'' G. melanomphax'' *'' G. moseri'' *'' G. nemorale'' *'' G. nitriolens'' *'' G. oligophyllum'' *'' G. pantoxanthum'' *'' G. pseudomurale'' *'' G. reclinis'' *'' G. sanguineum'' *'' G. schusteri'' *'' G. sericeum'' *'' G. stevensonii'' *'' G. strombodes'' *'' G. subchrysophyllum'' *'' G. subclavatum'' *'' G. suboreades'' *'' G. subsericellum'' *'' G. sucrense'' *'' G. tenue'' *'' G. theophili'' *'' G. umbilicatum'' *'' G. virgineum'' *'' G. viridilucens'' *'' G. xanthophyllum'' *'' G. zhujian''

Description

The species are small- to medium-sized

s with white, nonamyloid,

spores In biology, a spore is a unit of sexual (in fungi) 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 plant ...

and decurrent

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

. Typically the

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. The origin of the word "cap" comes from the Old French word "chapeau" which means "head co ...

of the fruit bodies have a shallow to deep central depression, giving the

umbrella An umbrella or parasol is a folding canopy supported by wooden or metal ribs that is mounted on a wooden, metal, or plastic pole. It is usually designed to protect a person against rain. The term ''umbrella'' is traditionally used when protec ...

-like to funnel-shaped caps the appearance of a belly button, or a belly with a

navel The navel (clinically known as the umbilicus; : umbilici or umbilicuses; also known as the belly button or tummy button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord. Structure The u ...

. At least one species, '' G. viridilucens'', is

bioluminescent Bioluminescence is the emission of light during a chemiluminescence reaction by living organisms. Bioluminescence occurs in multifarious organisms ranging from marine vertebrates and invertebrates, as well as in some fungi, microorganisms inc ...

Similar species

Similarly shaped agarics are said to be ''omphalinoid'' in appearance in reference to a morphologically similar genus, '' Omphalina''. ''Gerronema'' differ from ''Omphalina'' by the absence of incrusting or intraparietal

pigments A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

typical of ''Omphalina'', the occasional occurrence of bright colors, such as yellow or green absent in ''Omphalina'', by the restriction to decay of wood, and by the tough tissues composed of sarcodimitic hyphae.

Distribution and habitat

The species is a

with a primarily

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

distribution, but also occur in Europe and eastern North America where they fruit during hot muggy, summer weather. One of the most common species in the eastern United States is ''G. strombodes''.http://www.indianamushrooms.com/gerronema_strombodes.html

References

External links

*''Gerronema'' (Google Images

{{Taxonbar, from=Q3761254 Agaricales genera Taxa named by Rolf Singer Porotheleaceae