History of name:
Laccaria ochropurpureus
Berkeley, London J. Bot. 4: 299-300. 1845. Clitocybe ochropurpurea
(Berkeley) Saccardo, Syll. Fung. 5: 148. 1887. Laccaria ochropurpurea (Berkeley)
Peck, Annual Rep. New York State Bot. 116: 41. 1907. Clitocybe laccata
f. major Bresadola, Ann. Mycol. 18: 65. 1920.
Type: U.S.A.: Ohio, Cincinnati, no date, Lea 261 (K!, holotype).
Species Synopsis:
Pileus up to 125 mm broad, not striate, finely fibrillose, very light violaceous
brown to buff. Lamellae thick, waxy appearing, dark purple. Stipe most 45-190 X 6-22
mm, coarsely fibrillose, striate, occasionally reticulate near apex, concolorous
with pileus; basal mycelium violet. Basidia 4-sterigmate. Cheilocystidia 23 63.5
X 2.3-8.9 µm, undifferentiated to subclavate, abundant. Basidiospores mostly
7-9.5 X 7-9 µm (excluding ornamentation), globose to subglobose, echinulate;
spines mostly 1 1.4 µm long, 1-1.5 µm wide at base. Eastern North America,
associated with oaks and other Fagaceae.
Habitat and Distribution:
Solitary to scattered, rarely caespitose, commonly encountered in temperate deciduous
forests of eastern North America, probably in association with Quercus and
Fagus. Not reported from other continents. See Specimens
Examined for the list of specimens studied.
Observations:
Laccaria ochropurpurea can be distinguished easily from all other Laccaria
taxa by its large size, light violaceous brown to buff color pileus and stipe, dark
purple, thick, waxy lamellae, and globose to subglobose basidiospores. The only North
American species which could be confused with it are L. nobilis and faded
collections of L. amethysteo-occidentalis and L. trullissata.
These taxa all differ in basidiospore shape and size. In addition, L. amethysteo-occidentalis
differs in having numerous, large cheilocystidia while L. nobilis has reddish
brown to orange-brown, strongly scaly basidiomata. Collections of L. trullissata
have elongate, finely roughened basidiospores and are restricted to sand or sandy
soil with sand covering much of their stipe and adhering to their basidiomata.
Culture mat morphology of the five isolates utilized showed the least intraspecific
variation of all the taxa examined. The slow growth rate and dark purple color on
PDA were distinctive (Figure 44).
Laccaria ochropurpurea appears to be restricted to deciduous-coniferous
forests of eastern North America. Lahaie (1981) reported that it does not occur in
the coniferous boreal forests of eastern Canada. Several reports of L. ochropurpurea
occurring in western North America have been noted (personal communications and herbarium
specimens) but all of the specimens investigated during this study appeared to be
either L. amethysteo-occidentalis or L. nobilis.
Macromorphology:
Pileus 35-100(-125) mm broad, obtuse, convex, plane or uplifted, often depressed,
not striate, dry, subglaborous, finely fibrillose or occasionally fibrillose-scaly,
light violaceous brown to buff color, often with violaceous tints in young, fresh
specimens ("Vinaceous-Buff," "pale Vinaceous-Fawn" or "Pinkish
Buff"); margin inrolled, decurved, plane or uplifted, entire, slightly undulate,
eroded or rimose; context * 9 mm thick at disc, tapering to margin, violaceous buff.
Lamellae sinuate, arcuate or subdecurrent, close to distant, narrow to broad,
thick, waxy-appearing, dark purple ("Dark Heliotrope Gray" or "Deep
Vinaceous-Gray"). Stipe (15-)45-190 x (2-)6-22(-36) mm, equal, subclavate,
clavate or slightly bulbous, dry, coarsely fibrillose; fibrils forming longitudinal
striations, recurved scales or both, at times forming reticulations at maturity;
ground color concolorous with pileus; striations brownish to reddish brown. Basal
mycelium scant to copious, violet. Basidiospores in mass light violaceous
or white.
Micromorphology:
Pileipellis of tightly interwoven hyphae with occasional widely scattered
± perpendicular individual hyphae, not fasciculate; terminal cells 24-66.5 x
4-10 µm, filamentous or barrel-shaped, olive brown in mass; walls up to 0.5
µm thick, olive brown; contents hyaline, light olive brown or light yellowish
brown. Pileus trama tightly interwoven, morphologically undifferentiated,
hyaline, light yellowish brown to olive brown toward pileipellis. Lamellar trama
parallel; hyphae mostly 3-11.5 µm diam, thin-walled, hyaline to light yellowish
brown; cells barrel-shaped. Subhymenium morphologically undifferentiated.
Basidia 33-61.5 x 7-11.5 µm, clavate, hyaline; sterigmata (2-)4, up to
8 µm long. Cheilocystidia 23-63.5 x 2.3-8.9 µm, filamentous, subclavate
or subcapitate, abundant, thin-walled, hyaline. Basidiospores (excluding ornamentation)
[60/4] (6.4-)7-9.2(-11) x (6.4-)7-8.7 (-9.7) µm [ = 7.9-8.4 x 7.4-8.1 µm],
Q = (0.93-)1-1.13(-1.16) [ = 1.02-1.06], globose to subglobose, hyaline, echinulate;
echinulae 0.9-1.4(-2.3) µm long, 1-1.5 µm wide at base, crowded; hilar
appendix 1.3-2 µm long, prominent, truncate; plage present; contents occasionally
uniguttulate. Basal mycelium hyphae mostly 3.5-10.5 µm diam, tightly
interwoven, filamentous, hyaline.
Somatic Culture Mat Morphology
(n=3; Appendix B):
PDA: Radius at week 3 = 5-11 mm, week 6 = 7-23 mm; mat felty, thick,
tightly interwoven, tightly appressed to agar surface, in time forming pruinose aerial
layer away from plug, not translucent, at first bright violet, by week 6 violet coloration
restricted to 2-3 mm band near margin, short aerial hyphae light grayish violet;
margin 1-3 mm broad, thin, silky, becoming subfelty, even to uneven, light
violet to white; plug often covered with white cottony hyphae, bright violet;
hyphae morphologically undifferentiated, olivaceous brown in mass. MMN:
Radius at week 3 = 11-19 mm, week 6 = 23-39 mm; mat silky, subfelty or
felty, thin to thick, interwoven, tightly appressed to agar surface, translucent,
light violet, often with 1-3 concentric darker narrow bands; margin narrow,
subfelty to silky, thin, entire to sulcate, light violet; plug concolorous
with mat; hyphae morphologically undifferentiated. MEA: Radius at week
3 = 6-17 mm, week 6 = 10-33 mm; mat subfelty to felty, rarely silky, thin
to thick, interwoven, tightly appressed to agar surface, translucent, white; margin
not well differentiated, narrow, silky to subfelty, thin, even to undulate, white;
plug white; hyphae morphologically undifferentiated.