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Mycena alba (Bres.) Kühner

Encyclop. Mycol. 10: 594 (1938)

= Phloeomana alba (Bres. apud Sacc.) Redhead
in Index Fungorum no. 289 (2016)

© A. Aronsen
VESTFOLD, Tjøme 30 Oct. 2005

On moss-covered trunks of deciduous trees. Autumn. Regarded as NT in the Red List Of Threatened Fungi In Norway. Records in the Norwegian Mycology Database.

Pileus 2-10 mm across, hemispherical to convex or applanate with somewhat expanded margin, mostly with a depressed centre, but also with a small papilla, pruinose, glabrescent, sulcate, translucent-striate (disappearing when drying), at first white or beige, sometimes with a yellowish tinge in the centre, with age turning more brownish, dirty white, whitish-brown or pale brown with darker centre. Lamellae (6-)9-12 reaching the stipe, broad, arcuate to subhorizontal, the edge concave, broadly adnate, more or less decurrent, whitish. Stipe up to 12 mm long, more or less curved, equal or somewhat tapering downwards, minutely puberulous, towards the base often hirsute, whitish, with age turning brown from the base; the base covered with coarse, white fibrils. Odour none.

Basidia 23-27 x 7-9 µm, clavate, 4-spored and clamped, or 2-spored and clampless. Spores (7-)8-9(-11) x 6.5-8(-9.2) µm, Q = 1.0-1.2, Qav = 1.1, globose, smooth, non-amyloid. Cheilocystidia 17-34 x 5-10 µm, clavate to subcylindrical, clamped or clampless, somewhat curved to flexuous, apically broadly rounded. Pleurocystidia absent. Lamellar trama not vinescent in Melzer's reagent. Hyphae of the pileipellis 2.5-4.5 µm wide, clamped or clampless, smooth for the greater part, terminally covered with scattered, coarse, inflated, simple or broadly lobed excrescences 4.5-13.5 x 3-5 µm. Hyphae of the cortical layer of the stipe 2-3 µm wide, smooth, clamped or clampless, terminal cells (caulocystidia) clavate to irregularly shaped, clamped, smooth to very coarsely diverticulate or lobed.

According to Maas Geesteranus (1992: 461) Mycena alba is 4-spored and clamped, but to my experience it more often appears to be 2-spored and clampless. This is in accordance with Robich (2003: 363). A nice plate with micro-photos of the 4-spored form is shown at Galería micológica.

Mycena alba may be confused with M. hiemalis (Osbeck) Quél. The point is that not-quite-mature spores of M. hiemalis are just as globose as the mature ones of M. alba and of the same size. Also, it is not always easy to determine whether the lamellar edge in a young fungus is going to develop a convex outline (M. hiemalis) or a straight to concave one (M. alba). Maas Geesteranus (1992: 461) payed attention to these facts and provided some more distinguishing features.

Mycena hiemalis:

  • cheilocystidia fusiform to somewhat utriform
  • hyphae of the pileipellis with cylindrical, narrow excrescences

Mycena alba:

  • cheilocystidia clavate to subcylindrical
  • hyphae of the pileipellis with much inflated excrescences

Mycena hiemalis

Mycena hiemalis

Go to identification key for sect. Hiemales

 


Further images on the web:

Jean-Louis Cheype (Very nice!)

Jean-Louis Cheype (2)

http://users.skynet.be/deneyer.mycology/champis/mycena_alba_(yd)_1.htm

 

© Arne Aronsen 2002-2015