Lichenomphalia hudsoniana (images of British lichens)

A basidiolichen with the thallus composed of bluish green, discoid squamules ('Coriscium viride'), and a toadstool for the fruitbody: cap omphalioid, pallid white, pale cream, yellow, or (rarely) apricot, somewhat waxy in appearance, with a striate to sulcate, crenulate margin, gills paler, decurrent, stipe white to pale yellow, usually tinged lilac when young, typically 1–2 × cap diameter, surface minutely but densely pubescent. Microscopically the tissues lack clamp connections, gill trama of narrow, thin-walled, bidirectionally branched hyphae, spores ochre yellow in deposit (fide Elborne), ellipsoid, 6.5–9.5(–10)×4.5–5.5 µm (measurements from Elborne, 2008). On damp, peaty soil, generally at higher altitudes, but not uncommon at lower altitudes in exposed situations, reportedly occasionally on well rotted wood and other peaty debris.

Refs: Elborne (2008), 224; Smith et al. (2009), 554; Purvis et al. (1992), 404 (as Omphalina); Favre (1955), 45, plate IV,9 (colour illustration, as Omphalia luteovitellina); Barrasa & Rico (2001), 376-379 (photomicrographs, as Omphalina); Dobson (2005), 287 (photos, as Omphalina); Dobson (2011), 257-8 (photos); Dalby & Dalby (2005), 17 (photo, as Omphalina, squamules only); Jahns (1983), 260-1 (photo, squamules, as Coriscium viride); Ryman & Holmåson (1984), 258 (photo, as Omphalina); Holien & Tønsberg (2008), 206 (photo); Moberg & Holmåson (1984), 222 (photo, as Omphalina); Wirth (1995), 2: 618-9 (photo, as Omphalina); Breitenbach & Kränzlin (1991), 190-1 (photo, as Gerronema hudsonianum); Gulden et al. (1985), 13 (photo, as Omphalina); Hinds & Hinds (2007), 298 (photo, squamules only).

Differs from other Lichenomphalia species in the squamulose, Coriscium thallus. Deeper yellow variants can be confused with L. alpina, but this lacks the Coriscium squamules, has a ± smooth stem and quite different spores. The two species quite often occur in the same locations, but seem to have rather different ecology, L. hudsoniana on peaty mineral soil, L. alpina on pure peat. If on peaty debris from rotted coniferous wood, confusion with the non-lichenised Chrysomphalina grossula is also posible (Coriscium squamules would be absent but beware of immature Cladonia). Yellow or yellowish variants may also closely resemble non-lichenised, montane Hygrocybe species, notably H. citrinopallida, H. xanthochroa and H. lilacina, the latter two also with lilac on the stem.

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Images of British Lichens