Annulus (mycology)

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A ring can be seen on the stem of this Gymnopilus junonius mushroom. Gymnopilus junonius-02.jpg
A ring can be seen on the stem of this Gymnopilus junonius mushroom.

An annulus is the ring-like or collar-like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remnants of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. It can also be called a ring which is what the Latin word annulus directly translates as. [1] The modern usage of the Latin word originates from the early days of botany and mycology when species descriptions were only written in Latin. Outside of the formal setting of scientific publications which still have a Latin requirement, [2] it will often just be referred to as a ring or stem ring in field guides [3] and on identification websites. [4]

Contents

Ring descriptions

The way in which the structure and appearance of rings is described can vary with author and the description may only note the existence of a ring without providing specific information in cases where the ring lacks any notable features that would be useful to distinguish between similar species. Ring shapes and structures can also vary between specimens of the same species and change with the age of the mushroom so multiple descriptions are sometimes used. Even in species with distinctly identifiable rings they may not always be present or perfectly match descriptions so it can be beneficial to have multiple specimens to compare at different states of maturity. [4]

Some rings may be persistent and remain through the life of the mushroom or they may disappear with age. Such rings have a variety of synonymous terms associated with them such as fleeting, [5] ephemeral, [4] evanescent, [6] transient, [7] fugacious [8] or impermanent. These rings may peel away from the stem, fall apart or simply fade into the stem surface as it matures. Rings may also be described as fragile, [9] meaning easily torn or damaged and whilst some fragile rings could be considered permanent if undisturbed they are often likely to vanish due to their fragility. Some rings may be fixed in place and firmly attached to the stem whilst others may be movable [9] or mobile with the ability to slide up and down the stem either by hand or just falling down naturally with age. Fragile and movable rings can appear to vanish so examining the stem for traces of a ring zone [10] (or annular zone) [11] or the base for a detached ring can sometimes be helpful. Various combinations of these terms can be used to best describe the nature of the ring in a particular species.

Some common descriptions of the type of ring include: [12]

Texture/Flesh

The texture of the partial veil can exhibit specific characteristics which can aid in identification and these may persist in the ring once the cap has detached from it. These details may be similar to that of the cap surface or distinct from it.

Texture/surface descriptions include: [12]

Ring positions

The position of the ring can be an important factor to observe to aid in identification although it is often not included in descriptions as for some species it can be quite variable. The position may appear different from specimen to specimen due to the height of the stem or the age of the mushroom and in species with movable, fragile or otherwise detachable rings it may not always be a reliable factor to observe. However for species which otherwise look quite similar but exhibit differences in colouration, texture or staining above or below the stem ring, the position can be a useful factor to note. [4]

The common descriptions of positions are: [12]

See also

Related Research Articles

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<i>Amanita fulva</i> Species of fungus

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<span class="mw-page-title-main">Partial veil</span> Mushroom anatomy

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<i>Macrolepiota procera</i> Species of fungus

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<i>Amanita farinosa</i> Species of fungus

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<i>Amanita velosa</i> Species of fungus

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<i>Amanita brunnescens</i> Species of fungus

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<i>Cortinarius mucosus</i> Species of mushroom

Cortinarius mucosus, commonly known as the orange webcap or the slimy cortinarius, is a species of mushroom in the family Cortinariaceae. In North America, the species is more commonly associated with northern coniferous forests. The specific epithet is derived from the Latin word mucosus, meaning mucus.

<i>Leucocoprinus cepistipes</i> Species of fungus

Leucocoprinus cepistipes, is a species of fungus in the family Agaricaceae. It is also known by the common name onion-stalk parasol in reference to the bulbous stem base. It is typically found on wood debris, such as wood chips but may also grow in potted plants or greenhouses. Typical characteristics include a fine-scaled bell-shaped cap, a partial veil, and a tendency to bruise a yellow to brown when handled.

<i>Amanita flavoconia</i> Species of fungus

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<i>Amanita abrupta</i> Species of fungus

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<i>Pulveroboletus bembae</i> Species of fungus

Pulveroboletus bembae is a species of fungus in the family Boletaceae that was first described in 2009. It is known only from the rainforest of northern Gabon, a region known for its high level of species diversity. Like all boletes, P. bembae has fleshy fruit bodies that form spores in tubes perpendicular to the ground on the underside of the cap. These yellowish tubes form a surface of pores, each about 1–2 mm in diameter. The brownish caps may reach up to 3.5 cm (1.4 in) wide, and rest atop pale brown stems up to 5.5 cm (2.2 in) long. The stems have a woolly, whitish yellow ring of tissue that is short-lived, and may be absent in older specimens. The spores of P. bembae are spindle- or fuse-shaped, and have rough surfaces—a detail observable when viewed with scanning electron microscopy. The fungus grows in a mycorrhizal relationship with Gilbertiodendron dewevrei, the dominant tree species of the Guineo-Congolian rainforest. Other similar Pulveroboletus species in the area include P. annulus and P. croceus, which may be differentiated from P. bembae by a combination of macro- and microscopic characteristics.

<i>Amanita exitialis</i> Species of fungus

Amanita exitialis, also known as the Guangzhou destroying angel, is a mushroom of the large genus Amanita. It is distributed in eastern Asia, and probably also in India where it has been misidentified as A. verna. Deadly poisonous, it is a member of section Phalloideae and related to the death cap A. phalloides. The fruit bodies (mushrooms) are white, small to medium-sized with caps up to 7 cm (2.8 in) in diameter, a somewhat friable ring and a firm volva. Unlike most agaric mushrooms which typically have four-spored basidia, the basidia of A. exitialis are almost entirely two-spored. Eight people were fatally poisoned in China after consuming the mushroom in 2000, and another 20 have been fatally poisoned since that incident. Molecular analysis shows that the species has a close phylogenetic relationship with three other toxic white Amanitas: A. subjunquillea var. alba, A. virosa and A. bisporigera.

<i>Cortinarius cinnamomeus</i> Species of fungus

Cortinarius cinnamomeus, also known as the cinnamon webcap, is a basidiomycete mushroom of the genus Cortinarius. The fungus produces brown fruit bodies with caps up to 6 cm (2.4 in) wide and stems up to 12 cm (4.7 in) long. The closely crowded gills underside the cap are initially yellow before turning brown. Cortinarius cinnamomeus is common in damp places in coniferous forests. It is distributed throughout the temperate zone of the Northern Hemisphere.

<i>Cortinarius anomalus</i> Species of fungus

Cortinarius anomalus, also known as the variable webcap, is a basidiomycete fungus of the genus Cortinarius. It produces a medium-sized mushroom with a grayish-brown cap up to 5 cm (2 in) wide, gray-violet gills and a whitish stem with pale yellow belts below. The mushroom grows solitarily or in scattered groups on the ground in deciduous and coniferous forests. It is found throughout the temperate zone of the northern hemisphere.

<i>Amanita atkinsoniana</i> Species of fungus

Amanita atkinsoniana, also known as the Atkinson's amanita, is a species of fungus in the family Amanitaceae. The fruit body is white to brownish, with caps up to 12.5 centimetres in diameter, and stems up to 20 cm long. The surface of the cap is covered with brownish conical warts.

<i>Austrocortinarius australiensis</i> Species of fungus

Austrocortinarius australiensis, commonly known as the skirt webcap, is a species of mushroom in the family Cortinariaceae which is native to Australia and New Zealand. The white mushrooms appear in autumn and can grow very large, with their caps reaching 30 cm (12 in) in diameter.

Amanita groenlandica is a species of fungus in the family Amanitaceae. It has been placed in Amanita sect. Vaginatae.

Leucocoprinus subglobisporus is a species of mushroom-producing fungus in the family Agaricaceae.

Lepiota ochrospora is a species of mushroom producing fungus in the family Agaricaceae.

References

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  5. "Neolentinus lepideus, Train Wrecker fungus". www.first-nature.com. Retrieved 2022-08-06.
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  7. "Protostropharia (Stropharia) semiglobata, Dung Roundhead". www.first-nature.com. Retrieved 2022-08-06.
  8. Szczepkowski, Andrzej; Gierczyk, Błażej; Kujawa, Anna; Dobrzyński, Piotr (2022-05-08). "Macrofungal diversity of greenhouses at the Warsaw University Botanic Garden". Ecological Questions. 33 (2): 95–100. doi: 10.12775/eq.2022.018 . ISSN   1644-7298. S2CID   249724619.
  9. 1 2 "Glossary". biolwww.usask.ca. Retrieved 2022-08-06.
  10. Kuo, Michael (2019). "Glossary (MushroomExpert.Com) - Ring Zone". www.mushroomexpert.com. Retrieved 2022-08-06.
  11. "annular zone", Wiktionary, 2016-07-25, retrieved 2022-08-06
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