Gregarious among grass in open field and
in moss under Juniper. Autumn. Known from Norway, Finland and Sweden.
mm across, at first acutely conical, flattening with age
and becoming more or less irregularly campanulate, finally
plano-convex, more or less umbonate, or somewhat depressed
at the centre, little to shallowly sulcate, translucent-striate,
pruinose, glabrescent, viscid, covered with a gelatinous
separable pellicle, blackish grey, blackish brown to dark
grey-brown, paler when dry, often darker at the centre and
the margin. Context thin. Odour
indistinct or somewhat farinaceous. Lamellae
20-32 reaching the stipe, tender, arcuate, c. 1 mm
broad, more or less rugulose with age, decurrent with a
tooth, pale to dark grey, with a separable paler edge. Stipe
30-65 x 1.5-3.5 mm, hollow, egual or somewhat broadened
above, curved below, terete to somewhat depressed, smooth,
pruinose, glabrescent except for the apex, viscid, greyish,
usually darker below, covered with few fibrils at the base.
30-40 x 7-9 µm, slender-clavate, 4-spored, with sterigmata up to 6.5 µm long. Spores
9.2-10.3 x 4.7-5.4 µm, Q = 1.8-1.9, pip-shaped, smooth, weakly
18-32 x 5.5-7 µm, forming a sterile band, clavate, embedded in gelatinous matter, apically covered
with comparatively few, unevenly spaced, coarse, occasionally
curved, cylindrical to clavate excrescences 2.5-14.5 x 1.5-5.5
µm. Pleurocystidia absent.
Lamellar trama dextrinoid, brownish vinescent in Melzer's reagent. Pileipellis
an ixocutis of much branched, smooth, hyphae 1.5-2.5
µm wide, the
terminal cells 1-1.5 µm wide, apically
diverticulate and much branched, with the excrescences 0.9-3.5
x 0.9 µm. Hypoderm made up of parallell, inflated hyphae
up to 20 µm wide. Hyphae
of the cortical layer of the stipe 1.5-2.5
µm wide, embedded in gelatinous matter, smooth,
terminal cells not observed. Clamp connections present at all tissues.
Mycena agrestis is a species of section
(A.H. Sm. ex Singer) Maas Geest., of which only seven
species are known, four in North America and three in Europe.
Four species have, like M. agrestis, arcuate lamellae.
M. austinii (Peck) Kühner can be distinguished
because of its white pileus, presence of a basal disc and
smaller spores. M. mackinawensis A. H. Sm. is
different because of smaller spores, differently shaped
terminal cells of the hyphae of the pileipellis, and occurrence
on coniferous branches. M. vulgaris
(Pers.) P. Kumm. differs in having smaller spores, differently
shaped cheilocystidia, and occurrence with conifers. M.
geesterani Heykoop, Esteve-Raventós & Moreno,
recently described from Spain (Heykoop et al. 1992), is supposed to have much
smaller spores that are strongly amyloid, differently shaped
cheilocystidia and occurrence with conifers.
Because of the viscid appearance of the pileus
and stipe M. agrestis could be taken for a member
of sect. Hygrocyboideae. M. agrestis, however, never shows any yellow colours,
which are so conspicuous in most varieties of Mycena
epipterygia, and in the latter the lamellae are
ascending and adnate (although decurrent with a tooth),
never arcuate. The two varieties of M. epipterygia lacking yellow shades, var. fuscopurpurea and var. pelliculosa can in the field be separated from M. agrestis with arcuate lamellae. Besides, they can be distinguished on account of the microscopic features. In M. epipterygia the hyphae of the pileipellis are branched,
anastomosing, covered with simple to furcated or branched excrescences, often forming dense masses, not smooth as in M. agrestis; the hyphae of the cortical layer of the stipe are smooth to sparsely covered with excrescences (smooth in M. agrestis); terminal cells abundant, coarsely diverticulate (presumably absent in M. agrestis).
In 2009 Mycena agrestis was recorded for the first time in Finland (von Bonsdorff & Aronsen 2011), and 2011 it was found in Skåne, Sweden (L. Örstadius, pers. comm.).
TJØME, Moutmarka 7 Nov. 1992. A. Aronsen A 53/92
(L, no. 993.342-029); 9 Oct. 1993. A. Aronsen A 66/93 (holotype;
L, no. 993.342-087); 27 Oct. 1996, A. Aronsen A 34/96; 1
Nov. 1998, A. Aronsen A 4/98 (O); 2 Nov. 1999, A. Aronsen
A1/99 (O); 15 Oct. 2006, A. Aronsen A13/06.