History of name:
Laccaria laccata var. proxima
Clitocybe proxima Boudier, Bull. Soc. Bot. France 28: 91. 1881. Laccaria
proxima (Boudier) Patouillard, Hymeno. Eur.: 97. 1887. Laccaria laccata
var. proxima (Boudier) Maire, Bull. Soc. Mycol. France 24: 16. 1908. Clitocybe
laccata var. proxima (Boudier) Bresadola. 1927. Icon. Mycologia.: 43.
1927.
Type: Plate II, fig. 2 in Boudier, Bull. Soc. Bot France 28. 1881 (lectotype,
fide Mueller, 1991a). Epitype: FRANCE: Montemorency, November l9O4, Boudier
s.n. (as C. proxima) (PC! "neotype" fide Mueller, 1987).
Species Synopsis:
Pileus mostly 15-70 mm diam, not striate, reddish brown to orange brown. Lamellae
pinkish flesh color. Stipe mostly 24-72 X 3-10 mm, often finely longitudinal-striate,
concolorous with pileus; basal mycelium white. Basidia 4 sterigmate. Cheilocystidia
19-66.5 X 2.5-8.5 µm, undifferentiated to subclavate, often abundant. Basidiospores
8-11 X 7-9 µm (excluding ornamentation), mostly broadly ellipsoid to ellipsoid,
echinulate; spines mostly 0.5-1 µm long. Found throughout North America.
Habitat and Distribution:
Scattered to gregarious; terrestrial, associated most commonly with Pinaceae, occasionally
among mosses including Sphagnum; disturbed areas, early succession forests
or under young planted pines in reforested areas. Cosmopolitan; common. Found throughout
North America. See Specimens Examined for
a list of the specimens studied.
Observations:
Laccaria proxima can be distinguished from L. laccata by
its more robust, more strongly colored basidiomata, non-striate and slightly scaly
to scaly pilei, and more elongate, finely echinulate basidiospores. Laccaria
proxima is separated from L. montana in having smaller, more
finely echinulate basidiospores and the more robust habit of its basidiomata. Collections
of L. proxima can be differentiated from those of L. oblongospora by
having less elongate, larger basidiospores, white basal mycelium, and culture mats
that are white on MMN, PDA and N6:5 media. A discussion of various interpretations
of the name L. proxima is presented in the section on type specimens.
Mueller (1982, 1984, 1985) reported that cultures of some L. proxima were
violet to purple on PDA and MMN media. Upon further analysis of the collections from
which these violet culture mats were derived, it was determined that these specimens
were L. bicolor and not L. proxima. The basidiospores observed from
these collections were much smaller and had longer echinulae than those from other
collections referable to L. proxima. The basidiospore dimensions and cultural
characteristics fit my circumscription of L. bicolor.
Intra- and interspecific pairing studies have supported treatment of L. proxima
as a discrete species. No isolate of L. proxima has been found to mate
with any other putative taxa and no intraspecific intersterility groups have been
detected (Fries & Mueller, 1984; Mueller, unpublished data). Further support
for recognizing L. proxima as an autonomous species was obtained during analyses
of mtDNA and rDNA RFLPs of select species of Laccaria (Gardes et al.,
1990, 1991a). A low level of intraspecific heterogenity in mtDNA and rDNA RFLPs was
detected among the three isolates of L. proxima used in these analyses while
their RFLPs were distinct from the other tested taxa.
Laccaria proxima has been reported from throughout North America. It
has also commonly been collected in Europe (Clémençon, 1984; Contu, 1986;
Mueller, 1991a). Watling (1987) reported that L. proximella Singer
is the alpine equivalent of L. proxima. As discussed previously (Mueller,
1991a), I cannot support this contention based on the large number of collections
referable to L. proxima that I have examined from alpine and boreal
habitats in Europe and North America. My interpretation of L. proximella
is that it differs from L. proxima by having violet stains (or mycelium?)
at the stipe base and grows in very poor, rocky soil. I have collected material referable
to L. proximella in southern Argentina and Chile.
Macromorphology:
Pileus (7-)15-69(-83) mm broad, campanulate to convex, often becoming plane
to uplifted, some depressed, not striate, occasionally translucent-striate when faded,
finely fibrillose to fibrillose, some becoming fibrillose-scaly to scaly or squarrose
in age, hygrophanous, reddish brown to orange brown ("Auburn," "Sanford's
Brown," "Orange Rufous," "Hazel," "Cinnamon-Rufous"),
fading lighter ("Apricot Buff"); margin incurved to decurved, sometimes
becoming plane, entire to undulate, occasionally becoming eroded with age; context
thin, tapering quickly to margin, pinkish flesh color ("Japan Rose" to
"Shell Pink"). Lamellae sinuate to adnate, occasionally arcuate,
subdistant to distant, up to 10 mm broad, pinkish flesh color ("Flesh Color,"
"Pale Salmon Color"). Stipe (12-)24-72(-155) x 3-11 mm, equal to
subclavate, often slightly bulbous, dry, fibrillose, often longitudinally striate,
striations moderate to pronounced, most of stipe concolorous with pileus; base occasionally
darker ("Rood's Brown"), striations concolorous with pileus or darker red
("Hay's Russet," "Pecan Brown" or "Onion-skin Pink").
Basal mycelium white. Basidiospores white in mass.
Micromorphology:
Pileipellis of interwoven hyphae with scattered to numerous large fascicles
of ± perpendicular hyphae; fascicles composed of 15-30 or more hyphae; terminal
cells of fascicular hyphae 27.5-92 x 4.5-16(-30) µm, filamentous, subclavate,
clavate, broadly clavate, capitate or ventricose-rostrate; walls up to 0.5 µm
thick, light to moderate yellowish brown; contents hyaline to light yellowish brown.
Pileus trama tightly interwoven, morphologically undifferentiated, hyaline,
light yellowish brown toward pileipellis. Lamellar trama parallel; hyphae
mostly 3-19 µm diam, thin-walled, hyaline to light yellowish brown; cells filamentous
to barrel-shaped. Subhymenium morphologically undifferentiated. Basidia
(23-)33-62 x 8-15 µm, clavate, hyaline; sterigmata 4, up to 7 µm long.
Cheilocystidia 19-66.5(-92) x 2-8.5(-16.5) µm, filamentous to subclavate,
occasionally subcapitate, often abundant, thin-walled, hyaline. Basidiospores
(excluding ornamentation) [265/20] 8-11(-12.5) x (6.5-)7-8.7(-9.2) µm [ = (8.7-)9-11.5
x 6.7-8(-8.8) µm], Q = (1.07-)1.16-1.49(-1.58) [ = 1.24-1.34(-1.43)], broadly
ellipsoid, ellipsoid or occasionally oblong, hyaline, echinulate; echinulae 0.5-1
µm long, occasionally with one or two long echinulae (up to 2 µm long)
at apex, crowded; hilar appendix 1.3-2 µm long, prominent, truncate, plage present;
contents occasionally uniguttulate. Basal mycelium hyphae mostly 2.5-17.5
µm diam, tightly interwoven, hyaline; cells filamentous to barrel-shaped.
Somatic Culture Mat Morphology
(n=4; Appendix B):
PDA: Radius at week 3 = 3-17 mm, week 6 = 25.6-43 mm; mat felty, thick,
tightly interwoven, not translucent, most of uniform thickness or with slightly thicker
area near plug, in one (GMM 1525) forming concentric thicker-thinner bands, white
to light tan; margin 1-2 mm broad, abruptly thinner or not well differentiated,
silky to subfelty, thin, uneven, white; plug white or becoming olive; hyphae
morphologically undifferentiated. MMN: Radius at week 3 = (6.3-)16-32 mm,
week 6 = (18-)43-64 mm, mat subfelty to felty, relatively thin to moderately
thick, interwoven, translucent to not translucent, thicker near plug, uniform or
thinner towards margin, white; margin abruptly thinner or not well differentiated,
silky to subfelty, white; plug white; hyphae morphologically undifferentiated.
MEA: Radius at week 3 = 11-26 mm, week 6 = 30-51 mm; mat subfelty to
felty, thin to relatively thick, translucent, white; margin not well differentiated,
somewhat thinner, white; plug white; hyphae morphologically undifferentiated,
occasionally irregularly swollen.