History of name:
Laccaria laccata var.bicolor
Maire, Pub. Inst. Bot. Barcelona 3: 84. 1937. Laccaria proxima var.
bicolor (Maire) Kühner and Romagnesi, 1935. Flore Analytique des Champignons
Superieurs: 131. 1935. (nom. invalidum, Art. 33: 2 ICBN). Laccaria
bicolor (Maire) Orton, Trans. Brit. Mycol. Soc. 43: 177. 1960.
Laccaria laccata var. pseudobicolor M. Bon in Bon & Haluwijn, Doc.
Mycol. 12 (46): 42. 1982.
Misapplied name. -- Laccaria farinaceae sensu Singer non Hudson, Sydowia
Beih. 7: 8. 1973.
Type: SPAIN: Catalonia, Collado de Tosses, 7 October 1933 Maire s.n. (MPU!,
holotype).
Species Synopsis:
Pileus 8-70 mm broad, not striate, fibrillose to fibrillose scaly, pinkish flesh
color. Lamellae light vinaceous, fading to light pinkish flesh color. Stipe 23-85(-130)
mm long, longitudinal-striate, concolorous with pileus; basal mycelium violet, fading
white, often copious. Basidia 4-sterigmate. Cheilocystidia 25-55 X 3-8 µm, undifferentiated
to subclavate, absent to abundant. Basidiospores mostly 7-9 X 6-8 µm, subglobose
to broadly ellipsoid, echinulate; spines 1-1.8 µm long. Western North America
east to Michigan .
Habitat and Distribution:
Scattered, occasionally caespitose. Very commonly encountered on soil or among mosses
under conifers in western North America east to Ontario and Michigan. Specimens of
L. bicolor sensu lato from northeastern United States and the Atlantic provinces
of Canada are included under L. bicolor (see below). See Specimens Examined for the list of specimens studied.
Observations:
Laccaria bicolor is characterized by having moderate-sized basidiomata,
violaceous lamellae when fresh and copious violet mycelium at the stipe base. Laccaria
trichodermophora differs by having pinkish flesh-colored lamellae and sparse,
strongly hygrophanous, violet basal mycelium. Laccaria bicolor has been reported
from western and northern North America and Europe while L. trichodermophora
has only been reported form southeastern North America, Mexico and Costa Rica. The
large, scaly basidiomata of L. nobilis differentiates that taxon from L.
bicolor. Laccaria nobilis occurs sympatrically with L. bicolor
in North America but has not been reported from Europe. All three of these taxa have
distinct culture mat morphologies.
Mueller and Gardes (1991) summarized the results of intercollection pairing studies,
phenetic analyses, and analyses of mtDNA and rDNA for the L. bicolor complex.
Three intersterility groups were detected among 38 North American isolates tested.
Matings within a group were frequent while matings were rare between these intersterility
groups. The three intersterility groups were delimited during phenetic analyses indicating
that these groups differed morphologically. The two employed Swedish isolates were
completely intercompatible with one North American group but only partially intercompatible
with isolates of the other two groups. These results were more or less concordant
with data obtained by RFLP analysis of mtDNA and rDNA (Gardes et al., 1990,
1991a). The North American isolates formed a relatively homogeneous group and were
differentiated from the two Swedish isolates based on analyses of rDNA (Gardes et
al., 1990). In contrast, analyses of mtDNA detected divergence between the North
American intersterility groups but not between the Swedish isolates and North American
isolates (Gardes et al., 1991a). Based on a synthesis of these data, the Swedish
collections along with material from western North America and areas adjacent to
the Great Lakes were treated as Laccaria bicolor sensu stricto; L. nobilis
was circumscribed as a taxon with large, robust, scaly basidiomata occurring sympatrically
with North American material of L. bicolor; and material from the southeastern
United States with pinkish flesh-colored lamellae were treated as L. trichodermophora
(Mueller and Gardes, 1991).
Laccaria bicolor is one of the most common Laccaria taxa found
in the coniferous forests of western North America and the Great Lakes area. Collections
of L. bicolor sensu stricto were not encountered from southeastern United
States. Material of L. bicolor sensu lato from northeastern United States
or Atlantic provinces of Canada, while frequently encountered, was not available
to include in the studies of Mueller and Gardes (1991). Consequently, the occurrence
and distribution of these three species in that area is unknown and collections of
L. bicolor sensu lato from this region have been treated as L. bicolor
in this monograph.
Isolates of L. bicolor are very frequently used in applied studies on ectomycorrhizae
(Kropp and Langlois, 1990).
Macromorphology:
Pileus 8-70 mm broad, convex to plane, often depressed, not striate, finely
fibrillose, fibrillose-scaly or occasionally scaly, hygrophanous, pinkish flesh color
("Walnut Brown," "Onion-skin Pink," "Kaiser Brown"
or "Cinnamon-Rufous") fading to buff color ("Flesh Ocher," "Salmon
Buff" or near "Pale Salmon Color"); margin decurved to plane, entire
to undulate, often eroded; context thin, tapering quickly to margin, light vinaceous
("Pale Brownish Vinaceous" or "Hydrangea Pink"). Lamellae
adnate to arcuate, subdistant to distant, broad, thick, light vinaceous ("Pale
Purplish Vinaceous," "Pale Vinaceous" or "Hydrangea Pink"),
fading to pinkish flesh color ("Light Congo Pink" or "Shell Pink"),
then light flesh color ("Pale Flesh Color" or "Pale Salmon Color").
Stipe 23-85(-130) x 3-6(-10) mm, equal, subclavate or slightly bulbous, dry,
fibrillose, longitudinally striate, concolorous with pileus; striations concolorous
with ground color or slightly darker red brown. Basal mycelium copious, hygrophanous,
violet when fresh ("Dull Lavender" to "Pale Vinaceous-Lilac"),
becoming white.
Micromorphology:
Pileipellis of interwoven hyphae with numerous large fascicles of ±
perpendicular hyphae; fascicles composed of (15-)25-30 or more hyphae; terminal cells
of fascicular hyphae 27.5-76 x 6-18.5 µm, subclavate, clavate or rarely subcapitate;
walls up to 0.5 µm thick, light yellowish brown; contents hyaline to light yellowish
brown. Pileus trama tightly interwoven, morphologically undifferentiated,
hyaline to light yellowish brown towards pileipellis. Lamellar trama parallel;
hyphae mostly 2-13.5 µm diam, thin-walled, hyaline to light yellowish brown;
cells filamentous to barrel-shaped. Subhymenium morphologically undifferentiated.
Basidia 28.5-55 x 7.4 13 µm, clavate, hyaline; sterigmata 4, up to 9
µm long. Cheilocystidia 24.5-55 x 2.5-8 µm, filamentous to subclavate,
thin-walled, hyaline, absent to abundant. Basidiospores (excluding ornamentation)
[465/28] (5.5-)7-8.7(-10) x (5.5-)6-7.8(-9.2) µm [ = 7.0-8.4( 9) x 6.2-7.8 µm],
Q = 1-1.26(-1.36) [ = 1.05-1.23], subglobose to broadly ellipsoid, occasionally globose
or ellipsoid, hyaline, echinulate; echinulae 1-1.8 µm long, * 1 µm wide
at base; hilar appendix 1.3-2 µm long, prominent, truncate; plage present; contents
occasionally uniguttulate. Basal mycelium hyphae mostly 3.2-15.5 µm diam,
tightly interwoven, hyaline; cells filamentous to barrel-shaped.
Somatic Culture Mat Morphology:
(n=10; Appendix B):
PDA: Radius at week 3 = 11-32 mm, week 6 = 18-40(-54) mm; mat felty,
thick, tightly interwoven, tightly appressed to agar surface, in time forming pruinose
aerial layer away from plug, occasionally becoming furrowed due to irregular infolding
near plug, not translucent, bright violet, fading to light orange-brown, or remaining
bright violet; aerial hyphae light grayish violet, often covering most of mat by
week 6 and then masking mat color; margin 3-4 mm broad, subfelty, thin, light
violet to white; plug dark violet at first, becoming light orange-brown; hyphae
morphologically undifferentiated or irregularly swollen, violet in mass, pigment
intracellular. MMN: Radius at week 3 = 22-41 mm, week 6 = (31-)40-63 mm; mat
silky, subfelty or felty, thin or thick, loosely to tightly interwoven, occasionally
with three to four narrow concentric thicker bands, tightly appressed to agar surface,
translucent or not translucent, at first light violet or violet, soon buff, by week
3 violet color usually restricted to thicker bands and near margin; margin
2-4 mm broad, silky to subfelty, thin, loosely interwoven, even to serrate, light
violet; plug light violet; hyphae morphologically undifferentiated
or rarely irregularly swollen. MEA: Radius at week 3 = 19-43 mm, week 6 =
30-52 mm, TENN 42529 68 76 mm; mat subfelty to felty, thick, interwoven, occasionally
with small, scattered, thicker sectors, tightly appressed to agar surface, translucent,
white; margin 2-3 mm broad, subfelty, not well differentiated, often very
uneven, white; plug white; hyphae morphologically undifferentiated, occasionally
with a few scattered irregular swollen hyphae.