''Clitocybe amarescens'' is a species of

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) ...

fungus in the family

Tricholomataceae The Tricholomataceae are a large family of fungi within the order Agaricales. Originally a classic "wastebasket taxon", the family included any white-, yellow-, or pink-spored genera in the Agaricales not already classified as belonging to e.g. t ...

. Widely distributed in northwestern Europe, it was first described in 1969 by Finnish mycologist Harri Harmaja. It fruits in groups or in

fairy ring A fairy ring, also known as fairy circle, elf circle, elf ring or pixie ring, is a naturally occurring ring or arc of mushrooms. They are found mainly in forested areas, but also appear in grasslands or rangelands. Fairy rings are detectable by ...

s in

grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...

s. ''Amarescens'' signifies "tending to bitterness".

Description

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 this mushroom measures 3-6 cm across, and is

hygrophanous The adjective hygrophanous refers to the color change of mushroom tissue (especially the pileus surface) as it loses or absorbs water, which causes the pileipellis The pileipellis is the uppermost layer of hyphae in the pileus of a fungal fr ...

, coloured grey-brown when moist, and pale brown when dry. Initially, the shape is convex with an inrolled margin, though it flattens out and becomes depressed with age. In young specimens, the cap is darker and can have a powdery appearance ( pruinescence), though its surface is smooth. The stipe is a similar colour to the cap when moist, though darker when dry and is solid at first, though it becomes hollow with age. It is cylindrical, and its base is covered in densely matted hairs (tomentum), though rarely, it also has inconspicuous rhizoids too. The

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 ...

are moderately

decurrent ''Decurrent'' (sometimes decurring) 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 petio ...

, attached to the stipe at a 15-45° angle. They are pale brown when moist, though when dry, more or less the same colour as the cap. They are crowded and thickest in the middle, and occasionally forked at the stipe. The odour of the mushroom is "mushroom-like" though the older specimens can smell reminiscent of Cystoderma carcharias. The caps of adult specimens taste slightly bitter, though their stipes and younger specimens taste mushroom-like.

Microscopic details

The

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 ...

measure 6.4 -9.4 x 3.1-4.8 μm. they are congophilus and cyanophilous. They have an obtuse base, and range from elliptical to oblong in shape. The spores contain one large and a couple smaller guttules. The

spore print 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing warm orange ("tussock") color spore print. ...

is pale yellow to cream. The apiculus (part of spore which attaches to the

sterigmata In biology, a sterigma (: sterigmata) is a small supporting structure. It commonly refers to an extension of the basidium (the spore-bearing cells) consisting of a basal filamentous part and a slender projection which carries a spore at the tip ...

) measures 0.6-0.9 x 0.5-0. 6 μm. The

basidia A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

usually have 4 spores each, but sometimes, they only have 2. The epicutis of the cap is 40-80 μm thick. Cheilocystidia are absent. Clamp connections are present in all tissue.

Ecology

In southwest Finnland'', Clitocybe amarescens'' grows in rows, groups or clusters in moist or occasionally dry coniferous

heath A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and is characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a coole ...

forests. They grow in

Picea A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Northern hemisphere. ''Picea'' is the sole genus ...

needle litter and sometimes in heaps of straw. They are often found alongside Pleurozium or Hylocomium mosses. They grow throughout October in the eastern areas of

southwest Finland Southwest Finland (, ; ) is a Regions of Finland, region ('','' ) of Finland. It borders the regions of Satakunta, Pirkanmaa, Tavastia Proper, Tavastia Proper (Kanta-Häme), Uusimaa, and Åland. The regional capital and most populous city is Tu ...

. They are common throughout northwest Europe, where they grow from September to January, and additionally in nutrient rich grasslands.

Similar Species

''C. metachroa'' has a less infundibuliform and striped cap, and paler gills as well as having a different ecology. Clitocybe stercoraria has a greenish grey tint instead of brown.

References

External links

* {{Taxonbar, from=Q10428874 amarescens Fungi described in 1969 Fungi found in fairy rings Fungi of Europe Fungus species