Images of British Lichens
Megalaria grossa (Pers. ex Nyl.) Hafellner.
Thallus thin, effuse, lacking a distinct cortex, white to pale- or greenish-grey, smooth to minutely warted, sometimes cracked, without soredia; apothecia relatively large, to 1.5 or 2mm diameter, black, lecideine, flat, becoming convex, disc smooth to minutely wrinkled, proper margins glossy, becoming turned under (excluded) as apothecia mature. On basic-barked trees (e.g. Ash, Fraxinus, or Hazel, Corylus), generally in sheltered, old woodland, widespread but local and rare, more frequent in the north. Could be confused with Lecidella elaeochroma but chemical spot reactions negative.
Refs: Smith et al. (2009), 566; Purvis et al. (1992), 365; Dobson (2005), 258 (photo); Dobson (2011), 264-5 (photo); Wirth, Hauck & Schulz (2013), 1: 336, 2: 722 (photo); Holien & Tønsberg (2008), 171 (photo); Arup et al. (1997), 188 (photo); Thor & Arvidsson (1999), 285 (photo); Puntillo (1996), plate 24 (photo).
|On Hazel (Corylus avellana), Logie, Morayshire, August 2010, in wet weather, apothecia soaked and somewhat swollen (BLS meeting)|
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Uploaded September 2013