History of Name:
Laccaria montana

Laccaria montana Singer, Sydowia 7: 89. 1973.
Laccaria laccata var. montana Möller, Fungi of the Faeröes: 269. 1945.
Russuliopsis laccata var. rosella f. pusilla Larsen, Bot. Iceland, Vol. II, Part IV 9: 525. 1932. Laccaria laccata var. pusilla (Larsen) Singer, Bull. Soc. Mycol. France 83: 109. 1967. [non. L. laccata f. pusilla Schroeter in Cohn, Krypt.-Fl. Schlesien 3: 623. 1889 (= L. laccata)].
Type: SWITZERLAND: Valais, prope flumen Borgne de Ferpecle, 1955-1960 m alt., 11 July l971, Singer M5464 (F!, holotype).

Species Synopsis:


Pileus 6-35 mm broad, plicate striate, brownish orange. Lamellae pinkish flesh color. Stipe mostly 13-54 mm long, concolorous with pileus; basal mycelium white. Basidia 4-sterigmate. Cheilocystidia usually lacking or very scarce, undifferentiated. Basidiospores mostly 8.5-14 X 8-12 µm (excluding ornamentation), mostly subglobose to broadly ellipsoid, echinulate; spines 1-1.8 µm long, ¾ 1 µm wide at base. Restricted to alpine, arctic, or boreal habitats.

Habitat and Distribution:


Scattered to gregarious, occasionally caespitose; in poor soil, humus or among mosses; under Pinaceae, Betula or Salix; restricted to arctic, boreal, or montane habitats, common. See Specimens Examined for the list of specimens studied.

Observations:


Laccaria montana can be distinguished from L. laccata by having larger basidiospores and arctic to boreal distribution.
The apparent stability of basidial characters within Laccaria coupled with the potential functional differences between 2-sterigmate taxa (facultative homothallism) versus 4-sterigmate taxa (obligatory heterothallism?) are the justification that I use to treat L. montana and L. pumila as separate species. While there are differences in basidiospore size between these two taxa, these are probably due to the 4-sterigmate versus 2-sterigmate condition and are not independent character states.
Homokaryotic isolates from only two specimens of L. montana have been obtained to date. Repeated attempts to obtain either intra- or intercompatible pairings with isolates of either of these stocks have failed (Mueller, 1991c). Homokaryotic isolates of L. pumila have not been obtained, and consequently, no test of the putative genetic isolation between these two taxa has been undertaken. Multivariate morphometric analyses only loosely grouped together the two tested collections (Mueller, 1991c). Finally, data are not available on potential genetic divergence between L. montana and other taxa because representatives of L. montana were not included in the RFLP analyses carried out by Gardes et al. (1990, 1991a).
Laccaria montana is among the more common Laccaria taxa found at high elevations and northern latitudes. At least some of the reports of L. tetraspora from the arctic are, according to their descriptions and illustrations, L. montana (e.g., Kobayasi et al., 1967; Miller et al., 1982).

Macromorphology:


Pileus 6-35 mm broad, convex to plane, becoming uplifted, often depressed, occasionally umbonate when young, usually plicate-striate when fresh, fibrillose to finely fibrillose-scaly, hygrophanous, brownish orange ("Hazel" to "Cinnamon-Rufous"), fading to buff color; margin decurved to plane, entire to undulate, occasionally becoming eroded; context ¾ 1 mm thick at disc, flesh color ("Buff-Pink"). Lamellae sinuate to decurrent, close to distant, pinkish flesh color to light vinaceous ("Vinaceous-Pink"). Stipe 13-54(-101) x 2-4(-7) mm, equal or tapering slightly toward base or apex, occasionally swollen at base, occasionally caespitose, dry, fibrillose, not striate to moderately longitudinally striate, concolorous with pileus. Basal mycelium white. Basidiospores in mass white.

Micromorphology:


Pileipellis of interwoven hyphae with scattered fascicles of ± perpendicular hyphae; fascicles composed of 10-30 hyphae; terminal cells of fascicular hyphae 39-51 x 5.5-10 µm, filamentous to subclavate, light yellowish brown in mass; walls up to 0.5 µm thick, light yellowish brown; contents hyaline to light yellowish brown. Pileus trama tightly interwoven, morphologically undifferentiated, hyaline, light yellowish brown toward pileipellis. Lamellar trama parallel to subparallel, hyphae mostly 2.5-20 µm diam, thin-walled, hyaline to light yellowish brown; cells filamentous to barrel-shaped. Subhymenium morphologically undifferentiated. Basidia 34.5-55 x 10-15.5 µm, clavate, hyaline; sterigmata 4, up to 11 µm long. Cheilocystidia 32-55.5 x 3-4.5(-7.5) µm, filamentous to subclavate, rarely clavate, thin-walled, hyaline, only found in one collection. Basidiospores (excluding ornamentation) [120/6] (7.8-)8.5-14(-14.7) x (7-)8-12 µm [ = 9.4-12.6 x 8.5-10.5 µm], Q = 1-1.26(-1.33) [ = 1.07-1.2], globose to broadly ellipsoid, occasionally ellipsoid, hyaline, echinulate; echinulae (0.5-)0.9-1.8 µm long, ¾ 1 µm wide at base, not crowded to crowded; hilar appendix 1.3-2 µm long, prominent, truncate; plage present; contents occasionally uniguttulate. Basal mycelium hyphae mostly 3-21 µm diam, tightly interwoven, hyaline; cells filamentous to barrel-shaped.