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The Genus Laccaria  

[ Basidiomycetes > Agaricales > Hydnangiaceae . . . ]

by Michael Kuo

Laccaria species form a fairly easily recognized group of white-spored mushrooms. The gills are often thick and a little waxy, and are usually purple, pinkish, or (Caucasian) flesh-colored. The cap colors range from whitish to, more commonly, orangish brown or reddish brown--while a few species are purple. Laccarias are never slimy, which helps in separating them from the waxy caps, and their gills are attached to the stem but do not run down it, helping distinguish them from clitocyboid mushrooms.

Laccarias are mycorrhizal, forming symbiotic partnerships with trees. There is evidence that at least some species of Laccaria may serve as pioneers in disturbed ground or de-forested areas that have recently begun the long road of ecological succession that leads, eventually, to a "mature" ecosystem. Thus, for example, several species of Laccaria are frequently found in young pine plantations.

Laccaria identification is frequently a fairly easy matter of carefully observing the mushroom's ecology and visible features--but I hasten to add that there is a catch: you must, in some cases, have fresh, young specimens available in order to judge the color (whitish or lilac) of the basal mycelium, since the purplish fuzz notoriously fades to whitish, often doing so fairly early in development. Microscopic analysis is required in order to sift through a few species clusters, and includes spore morphology, "prong counting" (determining whether basidia are two- or four-spored), hunting for cheilocystidia, and assessing pileipellis details. Most microscopic features necessary for Laccaria identification can be accomplished with a successful Roman aqueduct section, mounted in KOH (2%) and stained with phloxine.

DNA evidence, so far, has upheld Laccaria as a "good" genus, though its precise position among the gilled mushrooms has not been thoroughly resolved. Mating studies have tended to support the species traditionally delimited by morphology, though they have also suggested that there may be some biological species that cannot be separated on the basis of their physical features; for example, Laccaria bicolor in North America appears to consist of at least two groups that are intersterile, and cannot "mate," though the mushrooms look the same to the naked eye and the microscope.

If you are an Internet mushroom junky, you should definitely visit Laccaria expert Greg Mueller's wonderful site, The Mushroom Genus Laccaria in North America, hosted at the Field Museum of Natural History in Chicago.


Laccaria proxima

Laccaria amethystina

Laccaria ochropurpurea

Laccaria ohiensis

Laccaria amethystina

Key to 20 Laccaria Species in North America  

1.Growing in sand.

1.Growing elsewhere.

2.Associated with live oak (Quercus virginiana) on the Gulf Coast; spores under 10 µ long.
Laccaria vinaceobrunnea
at Mueller's Laccaria

2.Not growing with live oak on the Gulf Coast; spores much longer than 10 µ.

3.Known only from eastern Canada; basal mycelium whitish; spores with clearly defined spines.
Laccaria maritima
at Mueller's Laccaria

3.Known from eastern North America and the Great Lakes region; basal mycelium purplish; spores roughened but without clearly defined spines.

4.Gills clearly purple (like, purple purple) when fresh, and usually remaining so as the mushroom matures.

4.Gills variously colored (vinaceous, flesh-colored, lilac, pinkish, etc.) but not clearly purple--or if pale purplish when young, soon fading to pinkish, flesh color, etc.

5.Growing in western North America under conifers.

5.Growing east of the Rocky Mountains, under hardwoods or conifers.

6.Mature cap over 4 cm across, purplish when young but soon buff, whitish, or pale brownish; stem as wide as 2-3 cm when mature.

6.Mature cap smaller than 4 cm across, variously colored; stem 1 cm wide or less when mature.

7.Associated with live oak (Quercus virginiana) on the Gulf Coast; cap purplish becoming brownish.
Laccaria vinaceobrunnea
at Mueller's Laccaria

7.Associated with oaks or beech in eastern North America; cap purple, fading to lilac or buff.

8.Associated with eucalyptus; cap 1-3.5 cm across, rusty reddish brown, fading to buff, faintly to moderately lined; stem 2-6 cm long; basidia 2-spored.

8.Not completely as above.

9.Mature cap under 3 cm across, strongly lined; stem less than 4 mm thick.

9.Mature cap usually larger than above, lined or not; stem usually thicker than above.

10.Stem 2-7 cm long, reddish brown, contrasting with paler overall color of mature cap.
Laccaria striatula
at Mueller's Laccaria

10.Stem shorter than above, colored more or less like the cap.

11.Growing under conifers, birches, or willows in arctic, boreal, or montane (near the tree line) areas.

11.Growing elsewhere.

12.Basidia 2-spored.

12.Basidia 4-spored.

13.Spores mostly elliptical, 8-10 x 7-8.5 µ, with spines about 1 µ long.
Laccaria pseudomontana
(see Osmundson+ 2005)

13.Spores mostly subglobose, 9-10 x 8.5-9 µ, with spines about 2 µ long.
Laccaria montana
at Mueller's Laccaria

14.Young cap with a wine-colored tinge that soon fades to reddish brown or orangish brown; basidia 2-spored; spores 10-15 µ long.
Laccaria tortilis
at Mueller's Laccaria

14.Young cap reddish brown or orangish brown, without a wine-colored tinge; basidia 4-spored; spores 8-9 µ long.

15.Spores with spines about 1 µ wide at the base; cap usually not strongly lined.
Laccaria laccata
(small forms)

15.Spores with spines featuring wide (> 1 µ) bases; cap often strongly lined.

16.Growing under hardwoods with no conifers nearby; not growing in sphagnum.

16.Growing under conifers, or growing in sphagnum.

17.Basal mycelium of fresh, young specimens lilac to purplish--though possibly soon fading to whitish.

17.Basal mycelium white in all stages of development.

18.Found under long-leaf pine (Pinus palustris) along the Gulf Coast; cap sometimes with purplish tones; spores elliptical, with spines under 1 µ long.
Laccaria oblongospora
at Mueller's Laccaria

18.Not completely as above.

19.Cap and stem conspicuously scaly; cheilocystidia always absent.
Laccaria nobilis
at Mueller's Laccaria

19.Cap and stem usually smooth, hairy, or finely scaly--but not conspicuously scaly on a regular basis; cheilocystidia usually present.

20.Cap pinkish to flesh-colored; cap surface with numerous but scattered perpendicular fascicles of interwoven hyphae.

20.Cap brownish orange to reddish brown, fading to buff; cap surface, at least over the disc, densely packed with perpendicular fascicles of interwoven hyphae, appearing nearly as a trichoderm.

21.Stem 7-14 cm long; growing in moss or sphagnum, usually with spruce, tamarack, or alder nearby.

21.Stem shorter than above; usually not growing in moss or sphagnum but, if so, with pines nearby.

22.Spores round or nearly so, with spines 1-2 µ long; cap usually orangish brown, usually smooth or very finely hairy, usually under 5 cm across.

22.Spores broadly elliptical, with spines .5-1 µ long; cap reddish brown to orangish brown, finely hairy becoming finely scaly with maturity, 2-7 cm across.


Fries, N. & G. M. Mueller (1984). Incompatibility systems, cultural features and species circumscriptions in the ectomycorrhizal genus Laccaria (Agaricales). Mycologia 76: 633–642.

Martin, F. et al. (2008). The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis. Nature 452: 88–92.

Mueller, G. M. (1984). New North American species of Laccaria (Agaricales). Mycotaxon 20: 101–116.

Mueller, G. M. (1987). Designation of type collections for Laccaria proxima, L. tortilis, and L. trullissata. Mycotaxon 28: 303–311.

Mueller, G. M. (1991). Laccaria longipes, a new North American species of the Laccaria laccata complex. Mycotaxon 40: 145–150.

Mueller, G. M. (1991). Laccaria laccata complex in North America and Sweden: Intercollection pairing and morphometric analyses. Mycologia 83: 578–594.

Osmundson, T. W., C. L. Cripps & G. M. Mueller (2005). Morphological and molecular systematics of Rocky Mountain alpine Laccaria. Mycologia 97: 949–972.

Vellinga, E. (1995). Laccaria. In Bas, C., Th. W. Kuyper, M. E. Noordeloos & E. C. Vellinga. Flora Agaricina Neerlandica. Volume 3. Rotterdam: A. A. Balkema. 96-103.

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Kuo, M. (2010, December). The genus Laccaria. Retrieved from the MushroomExpert.Com Web site: