''Lactarius pubescens'', commonly known as the downy milk cap, is a species of

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from t ...

in the family

Russulaceae The Russulaceae are a diverse family of fungi in the order Russulales, with roughly 1,900 known species and a worldwide distribution. They comprise the brittlegills and the milk-caps, well-known mushroom-forming fungi that include some edible ...

. It is a medium to large

agaric An agaric () is a type of fungus 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. In the UK, agarics are called "mushroom ...

with a creamy-buff, hairy

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. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...

, whitish

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 ...

and short stout stem. The fungus has a cosmopolitan distribution, and grows solitarily or in scattered groups on sandy soil under or near

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains ...

. Edibility: Ambiguous and controversial. In Russia is consumed after prolonged boiling followed by a marinating process. However it is reported to have caused gastro-intestinal upsets. Therefore, its consumption should not be recommended and this species considered toxic.

Taxonomy and phylogeny

The species was first named by German botanist Heinrich Schrader as ''Agaricus pubescens'' in 1794. Elias Magnus Fries gave it its current name in 1838. The species has also been treated as a

variety Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

of ''Lactarius controversus'' (as ''L. controversus'' var. ''pubescens'' by Gillet in 1876) and as both a subspecies (as ''Lactarius torminosus'' subsp. ''pubescens'' by

Paul Konrad Paul Konrad (1 April 1877 in Le Locle – 19 December 1948 in Neuchâtel) was a Swiss geometrician and amateur mycologist. From 1902 he was an employee of the Compagnie des Tramways de Neuchâtel, of which, he served as a director from 1938 t ...

and

André Maublanc André Pierre Jules Maublanc (24 July 1880, in Nantes – 30 April 1958, in Paris) was a French mycologist and plant pathologist. Beginning in 1902, he worked as a préparateur at the Station de Pathologie végétale in Paris. In 1912, he traveled ...

in 1935) and a variety (as ''L. torminosus'' var. ''pubescens'' by Lundell in 1956) of ''

Lactarius torminosus ''Lactarius torminosus'', commonly known as the woolly milkcap or the bearded milkcap, is a large agaric fungus. A common and widely distributed species, it is found in North Africa, northern Asia, Europe, and North America. It was first describ ...

''. ''Lactarius pubescens'' is classified in the

section Section, Sectioning or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sig ...

''Piperites'', subsection ''Piperites''. This includes related ''Lactarius'' species characterized by having a latex that does not become yellow upon exposure to air, and which does not stain freshly cut surfaces of the fruit body yellow. Based on

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis published in 2004, ''L. pubescens'' is most closely related to '' L. scoticus'' and '' L. tesquorum''. The mushroom is commonly known as the "downy milkcap". The specific epithet ''pubescens'' is derived from

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

, and means "becoming downy".

Description

The

is wide, obtuse to convex, becoming broadly convex with a depressed center. The margin (cap edge) is rolled inward and bearded with coarse white hairs when young. The cap surface is dry and fibrillose except for the center, which is sticky and smooth when fresh, azonate, white to cream, becoming reddish-orange to vinaceous (red wine-colored) on the disc with age. The

are attached to slightly decurrent, crowded, seldom forked, whitish to pale yellow with pinkish tinges, slowly staining brownish ochraceous when bruised. The stem is long, thick, nearly equal or tapered downward, silky, becoming hollow with age, whitish when young, becoming ochraceous from the base up when older, apex usually tinged pinkish, often with a white basal

mycelium Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates ...

. 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 muscles, fats and other loose connective tissues, but ...

is firm, white; odor faintly like geraniums or sometimes pungent, taste acrid. The

latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

is white upon exposure, unchanging, not staining tissues, taste acrid. 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 ...

is cream with a pinkish tint. The edibility of ''Lactarius pubescens'' has been described as unknown,

poisonous Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...

, and even edible. The spores are 6–8.5 by 5–6.5 µm, elliptic, ornamented with warts and ridges that sometimes form a partial reticulum, prominences up to 1.5 µm high, hyaline (translucent), and

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of 7–13 nm in diameter, a beta sheet (β-sheet) secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the huma ...

. The

cap cuticle The pileipellis is the uppermost layer of hyphae in the pileus of a fungal fruit body. It covers the trama, the fleshy tissue of the fruit body. The pileipellis is more or less synonymous with the cuticle, but the cuticle generally describes ...

is a layer of thin-walled hyphae.

Varieties

*''Lactarius pubescens'' var. ''betulae'' (A.H. Sm.) Hesler & A.H. Sm. 1979 *''Lactarius pubescens'' var. ''betularum'' (Bon) Bon 1985 *''Lactarius pubescens'' var. ''scoticus'' (Berk. & Broome) Krieglst. 1991

Ectomycorrhizae

The ectomycorrhizae that ''L. pubescens'' forms in association with ''

Betula pendula ''Betula pendula'', commonly known as silver birch, warty birch, European white birch, or East Asian white birch, is a species of tree in the family Betulaceae, native to Europe and parts of Asia, though in southern Europe, it is only found ...

'' and ''

Populus tremuloides ''Populus tremuloides'' is a deciduous tree native to cooler areas of North America, one of several species referred to by the common name aspen. It is commonly called quaking aspen, trembling aspen, American aspen, mountain or golden aspen, tr ...

'' has been grown in pure culture and described scientifically.

Similar species

''Lactarius scoticus'' Berk. & Broome is a small morphological mimic of ''L. pubescens'', growing in arctic-alpine birch. ''L. pubescens'' is often mistaken for ''L. torminosus'' which has larger spores (7–10 by 6–8 µm).

Habitat and distribution

The fruit bodies of ''L. pubescens'' are found scattered or in groups on the ground in wet areas under

and other hardwoods from August to October. The fungus is common all over temperate Europe and has been reported from eastern North America, the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Tho ...

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyomi ...

, and western Canada; its frequency of appearance is occasional. It is also found in Greenland, and was reported for the first time in Rome, Italy, in 1997.

Bioactive compounds

The marasmane

sesquiterpenoid Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many unique combinations. Biochemical modificatio ...

pubescenone and the

sesquiterpene Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many unique combinations. Biochemical modificat ...

aldehyde lactaral have been isolated from the fruit bodies of ''L. pubescens''.

References

Cite text

External links

Mushroom Observer
Images {{Taxonbar, from=Q653776 pubescens Fungi described in 1794 Fungi of North America Fungi of Europe Taxa named by Elias Magnus Fries