# Lactarius pubescens

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***Lactarius pubescens***, commonly known as the **downy milk cap**, is a species of [fungus](/source/Fungus) in the family [Russulaceae](/source/Russulaceae). It is a medium to large [agaric](/source/Agaric) with a creamy-buff, hairy [cap](/source/Pileus_(mycology)), whitish [gills](/source/Lamella_(mycology)) and short stout [stem](/source/Stipe_(mycology)). The fungus has a [cosmopolitan distribution](/source/Cosmopolitan_distribution), and grows solitarily or in scattered groups on sandy soil under or near [birch](/source/Birch).

In [Russia](/source/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](/source/Heinrich_Schrader_(botanist)) as *Agaricus pubescens* in 1794.[1] [Elias Magnus Fries](/source/Elias_Magnus_Fries) gave it its current name in 1838.[2] The species has also been treated as a [variety](/source/Variety_(botany)) of *Lactarius controversus* (as *L. controversus* var. *pubescens* by Gillet in 1876)[3] and as both a [subspecies](/source/Subspecies) (as *Lactarius torminosus* subsp. *pubescens* by [Paul Konrad](/source/Paul_Konrad) and [André Maublanc](/source/Andr%C3%A9_Maublanc) in 1935)[4] and a variety (as *L. torminosus* var. *pubescens* by Lundell in 1956)[5] of *[Lactarius torminosus](/source/Lactarius_torminosus)*.[6]

*Lactarius pubescens* is [classified](/source/Classification_(biology)) in the [section](/source/Section_(biology)) *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.[7] Based on [phylogenetic](/source/Phylogenetic) analysis published in 2004, *L. pubescens* is most closely related to *[L. scoticus](/source/Lactarius_scoticus)* and *[L. tesquorum](/source/Lactarius_tesquorum)*.[8]

The mushroom is [commonly](/source/Common_name) known as the "downy milkcap". The [specific epithet](/source/Specific_name_(botany)) *pubescens* is derived from [Latin](/source/Latin), and means "becoming downy".[9]

## Description

The [cap](/source/Pileus_(mycology)) is 2.5–10 cm (1.0–3.9 in) 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](/source/Wine_(color)) (red wine-colored) on the disc with age. The [gills](/source/Lamella_(mycology)) are attached to slightly decurrent, crowded, seldom forked, whitish to pale yellow with pinkish tinges, slowly staining brownish ochraceous when bruised.

The [stem](/source/Stipe_(mycology)) is 2–6.5 cm (0.8–2.6 in) long, 6–13 mm (0.24–0.51 in) 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](/source/Mycelia). The [flesh](/source/Trama_(mycology)) is firm and whitish;[10] the odor is faintly like geraniums or sometimes pungent, and taste is acrid. The [latex](/source/Latex) is white upon exposure, unchanging, not staining tissues, taste acrid. The [spore print](/source/Spore_print) is cream with a pinkish tint. The [edibility](/source/Edible_mushroom) of *Lactarius pubescens* has been described as unknown,[11] [poisonous](/source/Mushroom_poisoning),[12] and even edible.[13]

The [spores](/source/Spore) are 6–8.5 by 5–6.5 [μm](/source/Micrometre), elliptic, ornamented with warts and ridges that sometimes form a partial reticulum, prominences up to 1.5 μm high, [hyaline](/source/Hyaline) (translucent), and [amyloid](/source/Amyloid_(mycology)). The [cap cuticle](/source/Pileipellis) is a layer of thin-walled [hyphae](/source/Hypha).[11]

### 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](/source/Betula_pendula)* and *[Populus tremuloides](/source/Populus_tremuloides)* has been grown in pure culture and described scientifically.[14][15]

### Similar species

*Lactarius scoticus* Berk. & Broome is a small [morphological](/source/Morphology_(biology)) mimic of *L. pubescens*, growing in arctic-alpine birch.[16] *L. pubescens* is often mistaken for *L. torminosus* which has larger spores (7–10 by 6–8 μm).[17] Certain identification may require microscopic or genetic analysis.[10]

## Habitat and distribution

The fruit bodies of *L. pubescens* are found scattered or in groups on the ground in wet areas under [birch](/source/Birch) and other [hardwoods](/source/Hardwood) from August to October. The fungus is common all over temperate Europe and has been reported from eastern North America, the [Pacific Northwest](/source/Pacific_Northwest), [Arizona](/source/Arizona), [California](/source/California), [Colorado](/source/Colorado), [Idaho](/source/Idaho), and western Canada; its frequency of appearance is occasional.[11] It is also found in Greenland,[18] and was reported for the first time in Rome, Italy, in 1997.[19]

## Bioactive compounds

The marasmane [sesquiterpenoid](/source/Sesquiterpenoid) pubescenone and the [sesquiterpene](/source/Sesquiterpene) aldehyde lactaral have been isolated from the fruit bodies of *L. pubescens*.[20]

## See also

- [List of *Lactarius* species](/source/List_of_Lactarius_species)

## References

1. Schrader H. (1794). [*Spicilegium Florae Germanicae*](https://books.google.com/books?id=W4EVAAAAYAAJ&q=Spicilegium%20Florae%20Germanicae&pg=PA122) (in Latin). Hanover: Impensis Christiana Ritscheri. p. 122. Retrieved 2010-07-12.

1. Fries EM (1838). [*Epicrisis Systematis Mycologici, seu Synopsis Hymenomycetum*](https://books.google.com/books?id=sLQTAAAAQAAJ&q=Epicrisis%20Systematis%20Mycologici%2C%20seu%20Synopsis%20Hymenomycetum&pg=PA335) (in Latin). Upsaliae: Typographia Academica. p. 335. Retrieved 2010-07-12.

1. Gillet CC. (1876). *Les Hyménomycètes ou Description de tous les Champignons qui Croissent en France* [Hymenomycetes or descriptions of tall the mushrooms which grow in France] (in French). p. 210.

1. Konrad P, Maublanc A (1935). *Bull. Trimestriel Soc. Mycol. France*. **51**: 129.

1. Lundell S, Nannfeldt JA (1956). *Fungi Exsiccati Suecici*. **Fasc. 47-48**: 2301–2400.

1. ["Species synonymy: *Lactarius pubescens* (Fr.) Fr."](https://web.archive.org/web/20110610133239/http://www.indexfungorum.org/Names/SynSpecies.asp?RecordID=157260). *Index Fungorum*. CAB International. Archived from [the original](http://www.indexfungorum.org/Names/SynSpecies.asp?RecordID=157260) on 2011-06-10. Retrieved 2010-07-12.

1. Hesler & Smith, 1979, p. 237.

1. Nuytinck J, Verbeken A, Rinaldi AC, Leonardi M, Pacioni G, Comandini O (2004). ["Characterization of *Lactarius tesquorum* ectomycorrhizae on *Cistus* sp. and molecular phylogeny of related European *Lactarius* taxa"](http://www.mycologia.org/cgi/content/full/96/2/272). *Mycologia*. **96** (2): 272–82. [doi:10.2307/3762063](https://doi.org/10.2307/3762063). [JSTOR 3762063](https://www.jstor.org/stable/3762063). [PMID 21148854](https://pubmed.ncbi.nlm.nih.gov/21148854). Retrieved 2010-07-12.

1. Schalkwijk-Barendsen HME. (1991). [*Mushrooms of Western Canada*](https://archive.org/details/mushroomsofweste0000scha/page/215). Edmonton: Lone Pine Publishing. p. [215](https://archive.org/details/mushroomsofweste0000scha/page/215). ISBN 978-0-919433-47-2.

1. [Audubon](/source/Audubon) (2023). *Mushrooms of North America*. [Knopf](/source/Knopf). p. 180. ISBN 978-0-593-31998-7.

1. Bessette AR, Bessette A, Harris DM (2009). *Milk Mushrooms of North America: A Field Guide to the Genus*Lactarius'**. Syracuse: Syracuse University Press. pp. 228–29. ISBN 978-0-8156-3229-0.**

1. Phillips, Roger (2010 [2005]). [*Mushrooms and Other Fungi of North America*](https://archive.org/details/mushroomsotherfu0000phil). Buffalo, NY: Firefly Books. p. [112](https://archive.org/details/mushroomsotherfu0000phil/page/112). ISBN 978-1-55407-651-2.

1. Boa E. (2004). [*Wild Edible Fungi: A Global Overview Of Their Use And Importance To People (Non-Wood Forest Products)*](https://books.google.com/books?id=Zd2NlcNZgvcC&q=Lactarius+pubescens&pg=PA135). Food & Agriculture Organization of the UN. p. 135. ISBN 978-92-5-105157-3. Retrieved 2010-07-12.

1. Godbout C, Fortin JA (1985). "Synthesised ectomycorrhizas of aspen: fungal genus level of structural characterisation". *Canadian Journal of Botany*. **63** (2): 252–62. [doi:10.1139/b85-029](https://doi.org/10.1139/b85-029)

1. Ingleby K, Mason PA, Last FT, Fleming LV. 1990. Identification of ectomycorrhizas. London, UK: Institute of Terrestrial Ecology Research Publication No. 5, HMSO. 112 p.

1. Jahn H. (1982). "Über *Lactarius pubescens* und *L. favrei* sp. nov" (in German). *International Journal of Mycology and Lichenology*. **1**: 75–116.

1. Arora D. (1986). [*Mushrooms Demystified: a Comprehensive Guide to the Fleshy Fungi*](https://books.google.com/books?id=L-4ajFDPlxgC&q=Lactarius+pubescens&pg=PA73). Berkeley, CA: Ten Speed Press. p. 73. ISBN 978-0-89815-169-5. Retrieved 2010-07-12.

1. Knudsen H, Borgen T (1994). "The *Lactarius torminosus*-group in Greenland". *Mycologia Helvetica*. **6** (2): 49–56. [ISSN 0256-310X](https://www.worldcat.org/issn/0256-310X)

1. Perrone L. (1997). "Un alieno a Roma. Lactarius pubescens (Fr.) Fr. 1836" [A new record for Rome. *Lactarius pubescens* (Fr.) Fr. 1836] (in Italian). *Bollettino dell'Associazione Micologica ed Ecologica Romana*. **40**: 11–19.

1. Shao HJ, Wang CJ, Dai Y, Wang F, Yang WQ, Liu JK (2007). "Pubescenone, a new marasmane sesquiterpenoid from the mushroom *Lactarius pubescens*". *Heterocycles*. **71** (5): 1135–39. [doi:10.1002/chin.200741158](https://doi.org/10.1002/chin.200741158)

### Cite text

- Hesler LR, Smith AH (1979). *North American Species of*Lactarius'**. Michigan: The University of Michigan Press. ISBN 978-0-472-08440-1.**

## External links

- [Mushroom Observer](https://mushroomobserver.org/observer/observation_search?pattern=Lactarius+pubescens) Images

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Adapted from the Wikipedia article [Lactarius pubescens](https://en.wikipedia.org/wiki/Lactarius_pubescens) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Lactarius_pubescens?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.