Gerronema is a genus

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 small- to medium-sized lignicolous

Wood-decay fungus

A wood-decay fungus is a variety of fungus that digests moist wood, causing it to rot. Some wood-decay fungi attack dead wood, such as brown rot, and some, such as Armillaria , are parasitic and colonize living trees. Fungi that not only grow on wood but actually cause it to decay, are called...

 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 with white, nonamyloid

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...

, basidiospore

Basidiospore

A basidiospore is a reproductive spore produced by Basidiomycete fungi. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. In grills under a cap of one common species in the phylum of...

s and decurrent

Decurrent

Decurrent is a term used in botany and mycology to describe plant or fungal parts that extend downward.In botany, the term is most often applied to leaf blades that partly wrap or have wings around the stem or petiole and extend down along the stem...

 lamellae. The genus, first described by American mycologist 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....

 in 1951, contains 13 species.

Description

Typically 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...

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

Umbrella

An umbrella or parasol is a canopy designed to protect against rain or sunlight. The term parasol usually refers to an item designed to protect from the sun; umbrella refers to a device more suited to protect from rain...

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

Navel

The navel is a scar on the abdomen caused when the umbilical cord is removed from a newborn baby...

. Similarly shaped agarics are said to be omphalinoid in appearance in reference to a morphologically similar genus, Omphalina

Omphalina

Omphalina is a genus of small agarics with white, nonamyloid, basidiospores and decurrent gills. Typically the cap has a deep central depression giving the umbrella-like to funnel-shaped cap the appearance of a belly button, or a belly with a navel...

. Gerronema differ from Omphalina by the absence of incrusting or intraparietal 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...

s 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

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...

 hyphae.

Distribution

The species have a primarily tropical 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 U.S.A. is Gerronema strombodes http://www.discoverlife.org/nh/tx/Fungi/images/Gerronema_strombodes.Lorelei.300x328.jpg.htmlhttp://fp.bio.utk.edu/mycology/images/Gerronema_strombodes.htmhttp://www.indianamushrooms.com/gerronema_strombodes.html.

External links

• Gerronema (Google Images) http://images.google.com/images?hl=en&source=hp&q=Gerronema&um=1&ie=UTF-8&sa=N&tab=wi