Protostropharia semiglobata

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***Protostropharia semiglobata***, commonly known as the **dung roundhead**, the **halfglobe mushroom**, or the **hemispheric stropharia**, is an agaric fungus of the family Strophariaceae. A common and widespread species with a cosmopolitan distribution, the fungus produces mushrooms on the dung of various wild and domesticated herbivores. The mushrooms have hemispherical straw yellow to buff-tan caps measuring Template:Convert, greyish gills that become dark brown in age, and a slender, smooth stem Template:Convert long with a fragile ring.

## Taxonomy

The species was first described as *Agaricus semiglobatus* by August Batsch in 1786. It has had a complicated taxonomic history, having been shuffled to many different genera. In addition to *Agaricus* the species has been placed in *Coprinus*, *Geophila*, *Psalliota*, and *Psilocybe*. French mycologist Lucien Quélet gave it its most commonly used name in 1872 when he transferred it to *Stropharia*. In 2013, Scott Redhead made it the type species of *Protostropharia*, a new genus circumscribed to contain *Stropharia* species characterized by the formation of astrocystidia rather than acanthocytes on their mycelium. A form *sterilis* and two varieties, *minor* and *radicata*, described by F.H. Møller in 1945, are no longer considered to have independent taxonomic significance.

The specific epithet *semiglobata* is Latin for "half-spherical", and refers to the shape of the cap. It is commonly known as the halfglobe mushroom, the hemispheric stropharia, the round stropharia, or the dung roundhead.

## Description

 File:Stropharia semiglobata 38288.jpg
The cap is obtuse to hemispherical in shape, reaching a diameter of Template:Convert. The cap surface is smooth and sticky, and initially has a light yellow color that fades in maturity to dull yellow or whitish. The gills have an adnate attachment to the stem with a slight decurrent tooth. They are distantly spaced and broad–about 6–8 mm; mature gills become ventricose (swollen). The gills are initially grayish, but become purplish brown to dark purple as the spores mature. The edges of the gills are white and fringed. The stem is Template:Convert long by Template:Convert thick, with a bulbous base. Initially filled with a cottony pith, the stem becomes hollow in maturity. A delicate ring forms an annular zone on the mid to upper portion of the stem that may be darkened from spore deposits. Above the annular zone, the stem is covered with fine silk-like hairs; below, it is sticky. The stem tissue is white with a yellowish pith. The flesh has no distinctive odor, and a taste that is mild to slightly bitter. The fruit bodies have been listed as edible by some authors, but poisonous by others; even when not toxic, mushrooms that grow on dung are usually considered unpalatable, though the common mushroom is an obvious counter-example.

The mushroom produce a dark purple spore print. The thick-walled spores are ellipsoidal, smooth, and have a small apical germ pore; they measure 16.1–19.0 by 8.8–11.0 μm. The basidia (spore-bearing cells) are four-spored, club-shaped, hyaline (translucent), and measure 33–40 by 13–14.6 μm.

### Similar species

Other mushrooms that resemble *Protostropharia semiglobosa* include *Stropharia dorsispora*, *S. luteonitens*, and *Panaeolus semiovatus*.

## Habitat and distribution

A saprobic species, the fungus fruits in small groups on dung, in soil containing manure, on lawns, grasslands, or in livestock corrals. It has been recorded on the dung of a variety of wild and domesticated herbivores and ungulates, including rabbit, sheep, cow, buffalo, moose, bear, and wallaby. In some instances, the dung substrate is under moss so that it appears as if the mushroom is growing from the moss. Fruits bodies sometimes occur with another dung-loving fungus, *Deconica coprophila*. A widespread and common species, *P. semiglobosa* has a cosmopolitan distribution, having been recorded from northern Asia, Australia, Europe, Central and South America, North America, North Africa, and New Zealand. It is thought to have been introduced to Australia with imported domestic stock.

## References

1. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Batsch 1786`
2. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Quélet 1872`
3. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Redhead 2013a`
4. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Møller 1945`
5. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `urlMycoBank: Stropharia semiglobata`
6. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Evenson 1997`
7. ↑ 7.0 7.1 7.2 7.3 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Ammirati 1985`
8. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Bessette1997`
9. ↑ 9.0 9.1 9.2 9.3 9.4 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Roberts 2011`
10. ↑ 10.0 10.1 10.2 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Laursen 2009`
11. ↑ 11.0 11.1 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Miller 2006`
12. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Roody 2003`
13. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Noordeloos 1999`
14. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Smith 2005`

## External links

* Template:IndexFungorum

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