On moss-covered trunks of deciduous trees.
Autumn to early winter. Widespread, but rare in western lowlands, and not yet accepted from the UK. It is a rather common species in South Norway, especially on Acer platanoides and Fraxinus excelsior, but regarded as NT in the Norwegian Red List. Not recorded in the northern part of the country.
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.
23-27 x 7-9 µm, clavate, 4-spored and clamped, or 2-spored and clampless.
x 6.5-8(-9.2) µm, Q = 1.0-1.2, Qav = 1.1, globose, smooth, non-amyloid.
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
4.5-13.5 x 3-5 µm. Hyphae of the cortical layer
of the stipe
2-3 µm wide, smooth, clamped or clampless,
clavate to irregularly shaped, clamped, smooth to
very coarsely diverticulate or lobed.
According to Maas Geesteranus (1992: 461),
Phloeomana alba can be 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).
Phloeomana alba may be confused
with P. hiemalis (Osbeck)
Redhead. The point is that not-quite-mature spores of
P. hiemalis are just as globose as the mature ones
of P. 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 (P.
hiemalis) or a straight to concave one (P. alba).
Maas Geesteranus (1992: 461) payed attention to these facts
and provided some more distinguishing features.
- cheilocystidia fusiform to somewhat utriform
- hyphae of the pileipellis with cylindrical, narrow
- cheilocystidia clavate to subcylindrical
- hyphae of the pileipellis with much inflated excrescences