''Cortinarius praestans'', also known as the goliath webcap, is a

basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basi ...

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is t ...

of the genus ''

Cortinarius ''Cortinarius'' is a globally distributed genus of mushrooms in the family Cortinariaceae. It is suspected to be the largest genus of agarics, containing over 2,000 widespread species. A common feature among all species in the genus ''Cortinariu ...

''. The mushroom has orangish-yellow

caps Caps are flat headgear. Caps or CAPS may also refer to: Science and technology Computing * CESG Assisted Products Service, provided by the U.K. Government Communications Headquarters * Composite Application Platform Suite, by Java Caps, a Java ...

that reach up to in diameter, and thick club-shaped stipes up to long. The

edible mushroom Edible mushrooms are the fleshy and edible fruit bodies of several species of macrofungi (fungi which bear fruiting structures that are large enough to be seen with the naked eye). They can appear either below ground (hypogeous) or above ground ...

is found in Europe.

Taxonomy

The species was first described as ''Agaricus praestans'' by the French botanist François Simon Cordier in 1870. It is commonly known as the "goliath webcap".

Description

left Mature

are convex, usually grooved at the rolled-in margins, and typically reach diameters between . The surface color of the cap is

chestnut The chestnuts are the deciduous trees and shrubs in the genus ''Castanea'', in the beech family Fagaceae. They are native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce. The unrelat ...

or chocolate-brown with violet-copper tint. It has a light covering of surface fibrils and

veil A veil is an article of clothing or hanging cloth that is intended to cover some part of the head or face, or an object of some significance. Veiling has a long history in European, Asian, and African societies. The practice has been prominent ...

remnants that may appear as if pressed against the surface, or like small scales. 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 whitish with an amethyst tint then later creamy clay- to rust-colored. They are crowded closely together, and have edges that are usually wavy and scalloped. The

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

is long and thick, solid, and thickened at the base in an

emarginate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

bulb that is roughly club-shaped to

ventricose Ventricose is an adjective describing the condition of a mushroom, gastropod or plant that it is "swollen, distended, or inflated especially on one side". Mycology In mycology, ventricose is a condition in which the cystidia, lamella or stipe of a ...

. The stem surface is covered with silky fibrils, and is whitish-violet when very young, later losing the violet tones. The surface becomes fibrillosely floccose or whitish at the base and violet at the top, later becoming covered with the violet to whitish silky cortina (a cobwebby partial veil). The

flesh Flesh is any aggregation of soft tissues of an organism. Various multicellular organisms have soft tissues that may be called "flesh". In mammals, including humans, ''flesh'' encompasses muscle Skeletal muscles (commonly referred to as mu ...

is thick, whitish, and has a mild taste and no odor. The mushroom is considered a good

edible An edible item is any item that is safe for humans to eat. "Edible" is differentiated from "eatable" because it does not indicate how an item tastes, only whether it is fit to be eaten. Nonpoisonous items found in nature – such as some mushroo ...

species. 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 pinkish-tan spore print. A 3.5-centimeter ...

ochre Ochre ( ; , ), or ocher in American English, is a natural clay earth pigment, a mixture of ferric oxide and varying amounts of clay and sand. It ranges in colour from yellow to deep orange or brown. It is also the name of the colours produced ...

-rust colored. The

spore In biology, a spore is a unit of sexual 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 plants, algae, f ...

s are fusiformly lemon-shaped, densely covered with small "warts", and measure 15–17 by 8–10 μm. The edges of the gills have cystidiate hairs 4–6 μm wide, protruding 20-40 μm, and degenerate sterile

basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly-c ...

10–11 μm wide protruding 10–12 μm. The typical basidia measure 30–35 by 12–13 μm.

Distribution and habitat

The fruit bodies of the fungus grow in

deciduous forest In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

s, mainly on

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an adje ...

soils. It is common in western Europe, particularly England and France. It was one of 35 mushrooms to gain legal protection in

Hungary Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia a ...

in 2005, making it a fineable offense to pick them.

Research

''Cortinarius praestans'' extract has demonstrated antibacterial efficacy against ''

Pseudomonas aeruginosa ''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. aerugi ...

'' and ''

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive ...

''.Janeš D, Kreft S, Jurc M, Seme K, Štrukelj. (2007). Antibacterial Activity in Higher Fungi (Mushrooms) and Endophytic Fungi from Slovenia. Pharmaceutical Biology, 45, 9:700–70
https://www.researchgate.net/publication/259469827_Antibacterial_activity_in_higher_fungi_mushrooms_and_endophytic_fungi_from_Slovenia
/ref>

References

{{Taxonbar, from=Q613450 praestans Edible fungi Fungi described in 1826 Fungi of Europe

Taxonomy

Description

Distribution and habitat

Research

See also

References