History of Name:
Laccaria amethysteo-occidentalis

G. M. Mueller, Mycotaxon 20: 103-105. 1984. Type: CANADA: British Columbia, near Squamish, Alice Lake Prov. Park campground, 3 October 1981, G. M. Mueller 1256
(TENN No. 42526) (TENN!, holotype).

Species Synopsis:


Pileus mostly 10-65 mm broad, not striate, hygrophanous, deep purple when fresh, becoming vinaceous, eventually fading to buff. Lamellae dark violaceous, becoming vinaceous. Stipe up to 115 mm long, strongly striate, concolorous with pileus. Basidia 4-sterigmate. Cheilocystidia large (often up to 65 X 15 µm), subclavate to clavate , often very abundant. Basidiospores 8-10.5 X 7-9 µm, usually subglobose to broadly ellipsoid, echinulate; spines mostly 0.5-1.4 µm long. Western North America.

Habitat and Distribution:


Scattered to gregarious; under conifers [often Pseudotsuga menziesii (Mirb.) Franco] in western North America. See Specimens Examined for the list of specimens studied.

Observations:


Laccaria amethysteo-occidentalis can be distinguished easily from the other two "purple" Laccaria taxa found in North America, L. amethystina and L. vinaceobrunnea, by its large size and deeper purple coloration of fresh basidiomata. Additionally, L. amethysteo-occidentalis differs from L. amethystina in having non globose, more finely echinulate basidiospores and from L. vinaceobrunnea in the arrangement of the hyphae composing the pileipellis. All three taxa have large cheilocystidia which form a substerile layer along the lamellar margin. This character can be used in many cases to separate herbarium material of L. amethysteo-occidentalis from L. nobilis.
Homokaryotic isolates of this taxon were intersterile with isolates of other tested isolates including L. amethystina and L. vinaceobrunnea.
The above description of culture mat morphology was based on a single isolate, even though numerous attempts were made to culture from basidiomata of this species. The slow rate of growth and dark purple color of the culture mat on PDA were similar to that exhibited by cultures of L. ochropurpurea.
Laccaria amethysteo-occidentalis can be found commonly in the coniferous forests of northwestern United States and western Canada. In contrast L. amethystina appears to be restricted to the temperate deciduous or mixed coniferous-deciduous forests in eastern North America and Europe as well as tropical Quercus forests of Central America and Colombia.

Macromorphology:


Pileus 10-65 (-89) mm broad, obtuse, convex or plane, often depressed, not striate when fresh, occasionally becoming slightly translucent-striate upon fading, finely fibrillose, fibrillose or fibrillose-scaly, hygrophanous, deep purple when fresh ("Taupe Brown," "Dull Indian Purple," "Dusky Dull Violet 1," "Dark Hyssop Violet" or "Slate-Violet"), fading to vinaceous ("Dark Vinaceous-Drab," "Dark Vinaceous-Gray" or near "Wood Brown"), finally buff color (near "Pale Ochraceous-Salmon"); margin inrolled, decurved or plane, entire to eroded; context thin, concolorous with pileus ("Dark Slate-Violet") with lighter gray purple to white areas intermixed ("Pale Bluish Lavender").
Lamellae sinuate to arcuate, subdistant to distant, narrow to broad, thick, occasionally waxy appearing, dark violaceous ("Deep Slate Violet" to "Slate-Violet"), fading (near "Lavender").
Stipe 18 115 x 3-12 mm, equal, subclavate or slightly bulbose, dry, strongly longitudinally striate, occasionally with recurved scales, purple ("Dark Slate Purple," "Dark Vinaceous Brown" or "Hay's Brown"), often with lighter violet or white scattered sectors ("Pale Bluish Lavender"); context solid, concolorous with pileus context. Basal mycelium violet ("Dark Slate-Purple," "Deep Slate-Violet" or " Light Dull Bluish Violet"). Basidiospores white in mass.

Micromorphology:


Pileipellis of tightly interwoven hyphae with scattered fascicles of ± perpendicular hyphae, fascicles composed of 15-30 hyphae; terminal cells of fascicular hyphae 28-73.5 x 7-16 µm, filamentous, clavate or broadly clavate; walls up to 0.5 µm thick, vinaceous brown; contents hyaline to light vinaceous brown. Pileus trama tightly interwoven, morphologically undifferentiated, hyaline, light vinaceous brown toward pileipellis. Lamellar trama parallel; hyphae mostly 3 11.5 µm diam., thin-walled, hyaline to light vinaceous brown; cells barrel-shaped. Subhymenium morphologically undifferentiated. Basidia 34-56 x 10-14.5 µm, clavate, hyaline, in young specimens vinaceous brown in mass; sterigmata 4, up to 9 µm long. Cheilocystidia 36.5-66.5 x 12-18.5 µm, subclavate to clavate, often abundant, thin walled, hyaline. Basidiospores (excluding ornamentation) [81/6] 7.8-10.6 x 7-9.2 µm [ = 9-9.8 x 7.4-8.6 µm], Q = (1-)1.06-1.24(-1.36) [ = 1.13-1.19], subglobose to broadly ellipsoid, rarely globose or ellipsoid, echinulate; echinulae 0.5-1.4(-1.8) µm long, * 1 µm wide at base, crowded, hilar appendix 1.3-2 µm long, prominent, truncate; plage present; contents occasionally uniguttulate. Basal mycelium hyphae mostly 2.5-8 µm diam, hyaline, morphologically undifferentiated.

Somatic Culture Mat Morphology
(n=1; GMM 1256):


PDA: Radius at week 3 <3 mm, week 6 = 12-14 mm; mat felty, thick, tightly interwoven, tightly appressed to agar surface, not translucent, dark violet; margin up to 3 mm broad, subfelty, abruptly thinner than mat, entire, light violet; plug dark violet; hyphae mostly morphologically undifferentiated, occasionally subcoralloid. MMN: Radius at week 3 = 14-22 mm, week 6 = 24-32 mm; mat felty, thick, tightly interwoven, thicker near plug, tightly appressed to agar surface, not translucent, moderate violet, darker near plug, lighter colored away from plug; margin 1-2 mm broad, subfelty to silky, not well differentiated from mat, even to serrate, light violet; plug moderate violet; hyphae same as in PDA. MEA: Radius at week 3 = 14-17 mm, week 6 = 23-27 mm; mat subfelty, thick, interwoven with a narrow (3 mm) thicker band at midpoint, tightly appressed to agar surface, translucent, white; margin 1-2 mm broad, subfelty, not well differentiated, entire to somewhat serrate, white; plug white; hyphae morphologically undifferentiated.