Geopyxis carbonaria

Template:Taxobox

***Geopyxis carbonaria*** is a species of fungus in the genus *Geopyxis*, family Pyronemataceae. First described to science in 1805, and given its current name in 1889, the species is commonly known as the **charcoal loving elf-cup**, **dwarf acorn cup**, **stalked bonfire cup**, or **pixie cup**. The small, goblet-shaped fruitbodies of the fungus are reddish-brown with a whitish fringe and measure up to Template:Convert across. They have a short, tapered stalk. Fruitbodies are commonly found on soil where brush has recently been burned, sometimes in great numbers. The fungus is distributed throughout many temperate regions of the Northern Hemisphere. It is found in Europe, Turkey, and North America. Although it is primarily a saprotrophic species, feeding on the decomposing organic matter remaining after a fire, it also forms biotrophic associations with the roots of Norway spruce.

## Taxonomy

The fungus was first described scientifically in 1805 by Johannes Baptista von Albertini and Lewis David de Schweinitz as *Peziza carbonaria*. Mordecai Cubitt Cooke illustrated the fruitbodies, spores, and asci in his 1879 work *Mycographia, seu Icones fungorum. Figures of fungi from all parts of the world*. In 1889, Pier Andrea Saccardo transferred the fungus to the genus *Geopyxis*, giving the species its current name. *Pustularia carbonaria*, published by Heinrich Rehm in 1884, is a synonym of *G. carbonaria*. Louis-Joseph Grélet proposed the variety *Geopyxis carbonaria* var. *sessilis* in 1937, referring to forms producing fruitbodies without a stalk, but the taxon is not considered to have independent taxonomic significance. In 1860 Miles Berkeley and Moses Ashley Curtis described the species *Peziza lepida* from collections made in Japan as part of the North Pacific Exploring and Surveying Expedition (1853–1856). This taxon was synonymized with *G. carbonaria* by Mien Rifai in 1968, a taxonomic opinion corroborated by Donald Pfister about a decade later.

The specific epithet *carbonaria* derives from the Latin word for "charcoal". Common names given to the fungus include "charcoal loving elf-cup", "dwarf acorn cup", "pixie cup", and the British Mycological Society approved "stalked bonfire cup".

## Description

The fruitbodies (ascocarps) of *Geopyxis carbonaris* are cup shaped, 1–2 cm wide, and have fringed whitish margins. The inner spore-bearing surface of the cup, the hymenium, is brick red and smooth, while the exterior surface is a dull yellow, and may be either smooth or have blister-like spots (pustules). The stipe is small (1–1.5 mm long and 1–2 mm wide), whitish in color, and expands abruptly into the cup. The brownish flesh of the fungus is thin and brittle. It does not have any distinctive taste, but has an unpleasant smell when crushed in water. The edibility of the fungus is not known, but the fruitbodies are insubstantial and unlikely to be harvested for eating.

### Microscopic characteristics

In mass, the spores are whitish. The spores are elliptical, smooth, hyaline, devoid of oil droplets (*eguttulate*), and have dimensions of 13–18 by 7–9 µm. They are thin walled and germinate and grow rapidly in vitro in the absence of external stimuli. The asci are 190–225 by 9–10 µm. The paraphyses are slightly club-shaped, unbranched, and have irregular orange-brown granules, with tips up to 5 µm wide, and are not forked or lobed. The hypothecium, the layer of cells below the hymenium, is made of densely packed, small irregular cells.

### Similar species

 File:Geopyxis vulcanalis 85594.jpg
The closely related vulcan elf cup (*Geopyxis vulcanalis*) has a pale orange to yellowish fruitbody that is deeply cup shaped before flattening in maturity, and its crushed flesh often has an odor of sulfur. It may be distinguished microscopically by its paraphyses, which lack the orange-brown granules characteristic of *G. carbonaria*. It also has larger spores, measuring 14–22 by 8–11 µm. Unlike *G. carbonaria*, it grows on substrates other than burned wood, including mosses, and needle duff. *Tarzetta cupularis*, which grows habitats similar to *G. carbonaria*, is distinguished microscopically by its spores that contain two oil droplets. Other genera with similar species with which *G. carbonaria* may be confused in the field include *Aleuria*, *Caloscypha*, *Melastiza*, and *Sowerbyella*.

## Habitat and distribution

*Geopyxis carbonaria* is widespread on burned soil or charcoal in the spring and throughout the growing season. It is one of the most common pioneer species found on burned ground. The charred litter on the forest floor increases the underlying soil pH as well as the availability of minerals. Fruitbodies are produced from 16 to 139 weeks after a forest fire in areas with coniferous trees. Most fruitbodies are produced in the first year after a burn. The fungus prefers fruiting in microhabitats with thin postfire duff near standing burned tree trunks. *Geopyxis carbonaria* fruitbodies are often found in the same post-fire stands as morels, although the former is usually more abundant. Because the pixie cup fruits earlier than morels, it may serve as an indicator of imminent morel fruiting. Other cup fungi often found fruiting in the same area as *G. carbonaria* include those from the genera *Aleuria*, *Anthracobia*, *Peziza*, and *Tarzetta*.

The fungus is found in Europe (from where it was originally described), and is widespread throughout North America. The North American distribution extends north to Alaska. In 2010, it was reported for the first time from Turkey.

## Ecology

 File:Geopyxis carbonaria Kohlenbecherling.jpg
Although primarily a saprotrophic fungus involved in the post-fire breakdown of duff and coniferous roots, *Geopyxis carbonaria* has been shown to be capable of forming ectomycorrhizae with Norway spruce (*Picea abies*). It had been demonstrated earlier in laboratory experiments that the fungus has a biotrophic interaction with lodgepole pine (*Pinus contorta*). The hyphae of *G. carbonaria* were able to infect the cortex of the tree seedling, but did not penetrate the endodermis. These traits suggest that the fungus is a moderate pathogen, with limited ability to cause reductions in seed germination. Additionally, the fungus produces the enzyme polyphenol oxidase, and can break down the complex organic polymer lignin—features characteristic of saprotrophic fungi. The formation of a rudimentary Hartig net, a characteristic of mycorrhizal fungi, indicated that *G. carbonaria* might be capable of forming mutualistic relationships under the right conditions. Vrålstad and colleagues suggest that its below-ground association with spruce roots protects it from physical damage in the event of a fire, and the extensive fruitbody production after a fire may reflect "a successful fungal escape from a dying host where the fungus no longer can maintain its biotrophic association".

Large fruitings of the fungus are often associated with damage to the host tree, such as that which occurs with burning. A field study conducted in Norway demonstrated that fruit bodies were more likely to be found in areas that were heavily burned, compared to locations with light to moderate burning where the trees remained viable, or in clearcut areas. Fruiting was much denser in spruce forests—with up to 700–1000 fruitbodies per square meter—than in pine forests, where fruitbodies were sporadic. Fruitbodies grew by the millions in the year following the Yellowstone fires of 1988.

## References

1. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Albertini 1805`
2. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Cooke 1879`
3. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Saccardo 1889`
4. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Rehm 1884`
5. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `urlFungorum synonymy: Geopyxis carbonaria`
6. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `urlFungorum: Geopyxis carbonaria var. sessilis`
7. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Berkeley 1860`
8. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Pfister 1977`
9. ↑ 9.0 9.1 9.2 9.3 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Evenson 1997`
10. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `McKnight 1987`
11. ↑ 11.0 11.1 11.2 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Laursen 2009`
12. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `urlRecommended English Names for Fungi`
13. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Kupfer 1902`
14. ↑ 14.0 14.1 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Uzun 2010`
15. ↑ 15.0 15.1 15.2 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Tylutki 1979`
16. ↑ 16.0 16.1 16.2 16.3 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Vrålstad 1998`
17. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Beug 2014`
18. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Kimbrough 1990`
19. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Adl 2003`
20. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Petersen 1970`
21. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Greene 2009`
22. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Obst 2000`
23. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Lincoff 1989`
24. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Seaver 1928`
25. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Egger 1986`
26. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Egger 1986b`
27. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Egger 1986c`

## External links

Template:Commons category

* Template:IndexFungorum

Template:Taxonbar
Template:Good article