Fungus / parasite
colony of Calcarisporium anamorph of Calcarisporium arbuscula parasitises fruitbody of Lactarius
Fungus / saprobe
fruitbody of Collybia cirrhata is saprobic on decaying basidiome of Lactarius
Fungus / saprobe
sclerotium of Collybia tuberosa is saprobic on decaying basidiome of Lactarius
Fungus / parasite
live root of Epipogium aphyllum parasitises mycorrhiza of Lactarius
Other: minor host/prey
Fungus / parasite
Verticillium anamorph of Hypomyces ochraceus parasitises fruitbody of Lactarius
Fungus / parasite
subiculate, gregarious perithecium of Hypomyces viridis parasitises fruitbody of Lactarius
Other: major host/prey
Fungus / associate
larva of Mydaea humeralis is associated with Lactarius
Fungus / parasite
sporangium of Syzygites megalocarpus parasitises fruitbody of Lactarius
Candy cap or curry milkcap is the English-language common name for several closely related edible species of Lactarius; L. camphoratus, L. fragilis, and L. rubidus. These mushrooms are valued for their highly aromatic qualities and are used culinarily as a flavoring rather than as a vegetable.
Description and classification
Candy caps are small to medium-size mushrooms, with a pileus that is typically under 5 cm in diameter (though L. rubidus and L. rufulus can be slightly larger), and with coloration ranging through various burnt orange to burnt orange-red to orange-brown shades. The pileus shape ranges from broadly convex in young specimens to plane to slightly depressed in older ones; lamellae are attached to subdecurrent. The entire fruiting body is quite fragile and brittle. Like all members of Lactarius, the fruiting body exudes a latex when broken, which in these species is whitish and watery in appearance, and is often compared to whey or nonfat milk. The latex may have little flavor or may be slightly sweet, but should never taste bitter or acrid. These species are particularly distinguishable by their scent, which has been variously compared to maple syrup, camphor, curry, fenugreek, burnt sugar, Malt-O-Meal, or Maggi-Würze. This scent may be quite faint in fresh specimens, but typically becomes quite strong when the fruiting body is dried.
Microscopically, they share features typical of Lactarius, including round to slightly ovular spores with distinct amyloid ornamentation and sphaerocysts that are abundant in the pileus and stipe trama, but infrequent in the lamellar trama.
The candy caps have been placed in various infrageneric groups of Lactarius depending on the author. Bon defined the candy caps and allies as making up the subsection Camphoratini of the section Olentes. Subsection Camphoratini is defined by their similarity in color, odor (with the exception of L. rostratus – see below), and by the presence of macrocystidia on their hymenium. (The other subsection of Olentes, Serifluini, is also aromatic, but have very different aromas from the Camphoratini and are entirely lacking in cystidia.)
Bon and later European authors treated all species that were aromatic and had at least a partially epithelial pileipellis as section Olentes, whereas Hesler and Smith and later North American authors treat all species with such a pileipellis (both aromatic and non-aromatic) as the section Thojogali. However, a thorough molecular phylogenetic investigation of Lactarius has yet to be published, and older classification systems of Lactarius are generally not regarded as natural.
Like other species of Lactarius, candy caps are generally thought to be ectotrophic, with L. camphoratus having been identified in ectomycorrhizal root tips. However, unusually for a mycorrhizal species, L. rubidus is also commonly observed growing directly on decaying conifer wood. All candy cap species seem to be associated with a range of tree species.
|L. camphoratus||L. rubidus||L. fragilis|
|Pileus shape||papilla sometimes present at disc||papilla or umbo typically not present||umbo sometimes present at disc|
|Color||darker reddish-brown||more deep reddish-brown ("ferruginous")||lighter reddish-brown to light brown|
|Lamellae||more light yellowish to light orange||more light reddish||more light reddish|
|Spores||ellipsoid to subglobose; 7.0–8.5 x 6.0–7.5 µm; ornamentation not connected (spines to short ridges)||subglobose to globose; 6.0–8.5 x 6.0–8.0 µm; ornamentation semi-connected (broken to partial reticulum)||subglobose to globose; 6.0–7.5 x 6.0–7.5 µm; ornamentation connected (partial to complete reticulum)|
|Odor||more curry-like||more maple-like; strong only upon drying||more maple-like; strong, even when fresh|
|Distribution||Europe, Asia, eastern North America||western North America; also reported from Costa Rica||eastern North America|
|gills on hymenium|
cap is convexor flat
|hymenium is decurrent|
|stipe is bare|
spore print is whiteto yellow
|ecology is mycorrhizal|
It is possible to mistake other distasteful or toxic species of mushrooms for candy caps or mistakenly include in such species in a larger collection of candy caps. Those inexperienced with mushroom identification may mistake any number of little brown mushrooms ("LBMs") for candy caps, including the deadly galerina (Galerina marginata and allies), which can occur in the same habitat. Candy caps can be distinguished from non-Lactarius species by their brittle stipe, while most other "LBMs" have a more flexible stipe. It is therefore recommended that candy caps be gathered by hand, breaking the fragile stipe in ones fingers. By this method, LBM's with a cartilaginous stipe will easily be distinguished.
Candy caps may also be confused with any of a large number of small, similarly colored species of Lactarius that may be distasteful to downright toxic depending on the species and the number consumed.
- Odor: Candy caps have a distinctive odor (described above) that should not be present in other species of Lactarius. Note, however, that other species of Lactarius may have different, but also distinctive, odors. Also note that when fresh, candy caps (especially Lactarius rubidus) may not have a noticeable odor, limiting the utility of this characteristic.
- Taste: The flesh and latex of candy caps should always be mild-tasting to somewhat sweet, lacking any hint of bitterness or acridity. Note, however, that there are some species of Lactarius, such as L. luculentus, where the bitterness is subtle and also may not be noticeable for a minute or so after tasting.
- Latex: The latex of candy caps appears thin and whey-like, like milk that has been mixed with water. This latex does not change color nor does it discolor the flesh of the mushroom. Other species of Lactarius have a distinctly white or colored latex, which in some species discolors the flesh of the mushroom.
- Pileus: Candy caps never have a zonate pattern of coloration on the surface of the pileus, nor is the pileus ever even slightly viscid.
The chemical responsible for the distinct odor of the candy cap was isolated in 2012 by chemical ecologist and natural product chemist William Wood of Humboldt State University, from collections of Lactarius rubidus. The odoriferous compound found in the fresh tissue and latex of the mushroom was found to be quabalactone III, an aromatic lactone. When the tissue and latex is dried, quabalactone III is hydrolyzed into sotolon, an even more powerfully aromatic compound, and one of the main compound responsible for the odor of maple syrup, as well as that of curry.
The question of what compound was responsible for the odor of candy cap had been under investigation by Wood and various students for a period of 27 years, when a mycology student in a class he was teaching asked what compound was responsible for the mushroom's odor, triggering investigation into the question. Isolation of the compound remained elusive, until solid-phase microextraction was used to extract the volatile compounds, which were then analyzed using gas chromatography–mass spectrometry.
Earlier investigation of the aromatic compounds of L. helvus by Rapor, et al. had also yielded sotolon (among a large number of other aromatic compounds), which was identified as giving this species its distinct fenugreek odor. Other important volatile compounds identified included decanoic acid and 2-methylbutyric acid.
Analysis of Lactarius camphoratus has shown that it contains 12-hydroxycaryophyllene-4,5-oxide, a caryophyllene compound. However, this was not identified as an aromatic component of this mushroom.
Candy caps are not typically consumed as vegetable the way most other edible mushrooms are consumed. Because of the strongly aromatic quality of these mushrooms, they are instead used primarily as a flavoring, much the way vanilla, saffron, or truffles are used. They impart a flavor and aroma to foods that has been compared to maple syrup or curry, but with a much stronger aroma than either of these seasonings. Candy caps are unique among edible mushrooms in that they're often used in sweet and dessert foods, such as cookies and ice cream. They are also sometimes used to flavor savory dishes that are traditionally prepared with sweet accompaniments, such as pork, and are also sometimes used in place of curry seasoning.
They are usually used in dried form, as the characteristic aroma intensifies greatly upon drying. To use them as a flavoring, the dried mushrooms are either powdered or they are infused into one of liquid ingredients used in the dish, for example, being steeped in hot milk, much the same way whole vanilla beans are.
As a result of these culinary properties, candy caps are highly sought after by many chefs. Lactarius rubidus is commercially gathered and sold in California while L. camphoratus is gathered and sold in the United Kingdom  and Yunnan Province, China.
A number of species of Lactarius are distinctly aromatic, though only some of these species are thought to be closely related to the candy cap group.
The subsection Camphoratini includes Lactarius rostratus, a species found in northern Europe, though quite rare. Unlike other members of subsection Camphoratini, L. rostratus has an unpleasant (even nauseating) smell, described as resembling ivy. Lactarius cremor is a name sometimes used for mushrooms in this group, however, Heilmann-Clausen, et al. consider this name to be nomen dubium, referring variously to Lacarius rostratus, L. serifluus, or L. fulvissimus depending on the author's concept of L. cremor. Lactarius mukteswaricus and L. verbekenae, two species described from the Kumaon area of the Indian Himalaya in 2004, are reported to be very closely related to L. camphoratus and L. fragilis, respectively, including in odor.
Lactarius rufulus is reported by one source as being a "candy cap" species and having a similar odor to the other candy caps, though earlier monographs do not report such an aroma and describe the flavor as subacrid.
Lactarius helvus and L. aquifluus, found in Europe and North America, respectively, are also strongly aromatic and similar to candy caps, the former having the odor of fenugreek. Lactarius helvus is known to be mildly toxic, causing gastrointestinal upset. The edibility of L. aquifluus is unknown, but as it is a close relative of L. helvus, it is suspected of being toxic.
Lactarius glyciosmus and L. cocosiolens both have a distinct coconut odor. L. glyciosmus, however, has a subacrid flavor, though it is reported as having been gathered commercially in Scotland.
- Largent DL, Baroni TJ. 1988. How to Identify Mushrooms to Genus VI: Modern Genera. Arcata, CA: Mad River Press. ISBN 0-916422-76-3. p 73–74.
- Bon M. 1983. Notes sur la systématique du genre Lactarius. Documents Mycologiques 13(50): 15–26.
- Heilmann-Clausen J, Verbeken A, Vesterholt J. 1998. The Genus Lactarius. (Fungi of Northern Europe, Volume 2.) Mundelstrup, DK: Danish Mycological Society. ISBN 87-983581-4-6.
- Hesler LR, Smith AH. 1979. North American Species of Lactarius. Ann Arbor: University of Michigan Press. ISBN 0-472-08440-2.
- Methven AS. 1997. The Agaricales of California 10. Russulales II: Lactarius. Eureka, CA: Mad River Press. ISBN 0-916422-85-2.
- Mueller GM, Halling RE, Carranza J, Mata M, Schmit JP. 2006. Saprotrophic and ectomycorrhizal macrofungi of Costa Rican oak forests. In: M. Kappelle (ed). Ecology and conservation of neotropical montane oak forests. (Ecological Studies Series, Vol. 185). Berlin: Springer Verlag. p 55–68 (p 62). doi:10.1007/3-540-28909-7_5 ISBN 978-3-540-28908-1.
- Campbell D. 2004. The candy cap complex. Mycena News 55(3):3–4. (scroll down)
- Wood WF, Brandes JA, Foy BD, Morgan CG, Mann TD, DeShazer DA. 2012. The maple syrup odour of the “candy cap” mushroom, Lactarius fragilis var. rubidus. Biochemical Systematics and Ecology 43:51-53. doi:10.1016/j.bse.2012.02.027.
- Humboldt State University. 2012. Student question about mushroom’s maple syrup odor takes 27 years to answer. Humboldt State Now (website). May 04, 2012.
- Rapior S, Fons F, Bessiere J-M. 2000. The fenugreek odor of Lactarius helvus. Mycologia 92(2): 305–308. doi:10.2307/3761565.
- Daniewski WM, Grieco PA, Huffman JC, Rymkiewicz A, Wawrzun, A. 1981. Isolation of 12-hydroxycaryophyllene-4,5-oxide, a sesquiterpene from Lactarius camphoratus. Phytochemistry. 20(12):2733–4. doi:10.1016/0031-9422(81)85276-4.
- Treviño L. 2004 Jan 9. "Candy Caps let people flavor foods — with fungus: Mushrooms are in cookies and ice cream". San Francisco Chronicle.
- Jung C. 2004 Jan 28. "The rare fungus that can satisfy your sweet tooth". San Jose Mercury. (Archived at Wayback Machine),
- Kirby T. 2006 Sep 27. "The British fascination with fungi: The magic of the curry mushroom". The Independent.
- Wang X-H. 2000. (A taxonomic study on some commercial species in the genus Lactarius (Agaricales) From Yunnan Province, China.) Acta Botanica Yunnanica 22(4):419–427. (Article in Chinese. English abstract.)
- Marchand A. 1980. Champignons du Nord et du Midi 6: Lactaires et Pholiotes. Perpignan, FR: Diffusion Hachette. ISBN 2-903940-03-7.
- Das K, Sharma, JR, Montoya L. 2004. Lactarius (Russulaceae) in Kumaon Himalaya 1: New species of subgenus Russularia. Fungal Diversity 16:23–33. (Abstract.)
- Phillips R. 2006. Lactarius aquifluus. Roger's Mushrooms (website). Accessed 2008 Feb 11.
- Russulales News Team. 2007. Lactarius glyciosmus. Russulales News (website). Accessed 2008 Feb 11.
- Milliken W, Bridgewater S. nd. Scottish plant uses: Lactarius glyciosmus. Flora Celtica online database, Royal Botanic Garden, Edinburgh. Accessed 2008 Feb 11.
- Arora D. (1986). Mushrooms Demystified (2nd ed). Berkeley, CA: Ten Speed Press. ISBN 0-89815-169-4
- "Lactarius cilicioides (Fr.) Fr. 1838". MycoBank. International Mycological Association. http://www.mycobank.org/MycoTaxo.aspx?Link=T&Rec=233290. Retrieved 2012-03-18.
Lactarius is a genus of mushroom-producing fungi. The genus, collectively known commonly as milk-caps, are characterized by the fact that they exude a milky fluid ('latex') if cut or damaged. Like the genus Russula, with which they are grouped in the family Russulaceae, their flesh has a distinctive brittle consistency.
Often the gills are decurrent (starting to run down the stem) and the cap is depressed or even funnel-shaped when older. The stem and cap sometimes show 'strobicules' (or 'strobiculi'), which are flat-based shallow oval pits.
To identify to which of the roughly 400 Lactarius species a given specimen belongs, note whether the cap is bald/greasy or velvety or hairy/shaggy at the rim, particularly in young individuals. Also the initial colour of the milk (white, cream, orange, violet, ...) and the final colour on drying are determining characteristics.
Lactarius is one of the most prominent genera of ectomycorrhizal fungi. With more than 400 species described worldwide, Lactarius taxa play a significant role as late-stage colonizers of trees and shrubs in a vast range of ecosystems, from boreal coniferous forests to temperate Mediterranean-type maquis. An interesting case is that of the strict association of selected Lactarius species - such as L. tesquorum and L. cistophilus - with Cistus spp., a group of about 20 woody, evergreen or semideciduous shrub species found in wide semi-arid areas from the Canary Islands throughout the Mediterranean region to the Caucasus. Cistus species are obligate seeding, early colonizers that follow disturbance, particularly fire, in low maquis-type Mediterranean ecosystems, rendering their ectomycorrhizal ecology particularly intriguing.
A selection of well-known European species
- Lactarius turpis - ugly milk-cap
- Lactarius torminosus - woolly milk-cap
- Lactarius piperatus - peppery milk-cap
- Lactarius uvidus
This group of mushrooms has orange or red milk and carrot-orange coloration, in many cases becoming flecked with green or blue-green with age. They are all generally considered to be edible and tasty, the appetizingly named Lactarius deliciosus reputedly being much better than the others. They grow in coniferous woods.
L. deliciosus is the only one with an English name: 'saffron milk-cap'. It is found under pine or spruce. L. deterrimus was formerly considered to be a variety of L. deliciosus and is distinguished by the milk turning wine-red on drying - but only after up to 30 minutes. L. salmonicolor is associated with spruce and remains a pure orange, unlike the other two which discolour green.
The milk of this mushroom emerges white but immediately changes to a deep yellow colour. The top of the cap is a pinkish red with concentric zoning on a background showing yellow tints. It is common under broad-leaved trees, especially oak. There are conflicting reports as to its edibility.
This flesh-coloured Lactarius is closely related to L. chrysorrheus, and again the milk is initially white and turns yellow, but only after several seconds. To allow the milk to contact the air this is best tested on a paper tissue (a cloth handkerchief is liable to be permanently stained).
L. quietus, which is commonly found under oak trees, is often thought to be a non-descript mushroom, and in fact that is the significance of its Latin epithet quietus. It has a distinctive smell said to be of bedbugs or of wet laundry. The milk goes a little cream but does not change further.
- Rinaldi, A.C.; Comandini, O.; Kuyper, T.W. (2008). "Ectomycorrhizal fungal diversity: separating the wheat from the chaff". Fungal Diversity 33: 1–45. http://www.fungaldiversity.org/fdp/sfdp/33-1.pdf.
- Nuytinck, J.; Verbeken, A.; Rinaldi, A.C.; Leonardi, M.; Pacioni, G.; Comandini, O. (2004). "Characterization of Lactarius tesquorum ectomycorrhizae on Cistus sp. and molecular phylogeny of related European Lactarius taxa". Mycologia 96 (2): 272–282. doi:10.2307/3762063. PMID 21148854. http://www.mycologia.org/cgi/content/full/96/2/272.
- Comandini, O.; Rinaldi, A.C. (2008). "Lactarius cistophilus Bon & Trinbach + Cistus sp". Descriptions of Ectomycorrhizae 96: 83–88.
- Partly from Dutch Wikipedia pages.
- Meinhard Moser, translated by Simon Plant: Keys to Agarics and Boleti (Roger Phillips 1983)
- Régis Courtecuisse, Bernard Duhem : Guide des champignons de France et d'Europe (Delachaux & Niestlé, 1994–2000). ISBN 2-603-00953-2
- Roger Phillips : Mushrooms and other fungi of Great Britain and Europe (Pan Books Ltd. 1981 / Book Club Associates 1981) - for the English names.
- Verbeken, Annemieke (2001). "Worldwide systematics of Lactarius: a state of art". Micologia e vegetazione mediterranea 16 (1): 71–88.
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