Images of British Lichens
Pyrenula occidentalis (R.C. Harris) R.C. Harris
Thallus thin or more or less immersed, smooth, somewhat waxy, creamy brown, forming a narrow, black prothallus where adjacent thalli meet, surface lacking pseudocyphellae; perithecia numerous, conspicuous, up to 1mm in diameter, black, globose, projecting above the thallus surface, ostioles terminal, surface of perithecial apex in microscopic section giving purple-red reaction with potassium hydroxide (may also be seen in thallus sections). On smooth, rather shaded, nutrient-rich bark in oceanic woodland in western Britain, primarily in the "celtic rainforest" of western Scotland.
Refs: Refs: Smith et al. (2009), 779; Purvis et al. (1992), 522; Orange (2008); Dobson (2005), 379 (photo); Dobson (2011), 381 (photo); Holien & Tønsberg (2008), 204 (photo); Puntillo (1996), plate 35 (photo).
|On Hazel (Corylus avellana), Craighouse, Isle of Jura, May 2011, BLS meeting|
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Uploaded November 2012