Images of British Lichens
Sclerophora pallida (Pers.) Y.J.Yeo & Spooner
(= S. nivea (Hoffm.) Tibell)
Description (primarily based on concept of Giavarini & Purvis, in Smith et al., 2009): a minute 'pin lichen' with stalked, yellow-pruinose apothecia (mazaedia) (later greyer and epruinose), 0.4–0.7 mm in height, stalk pale yellow, becoming grey (or evidently red-brown) with maturity, without a darker core, standing up from a thin, immersed, crustose thallus; ascospores colourless, globose and warted, 7–8 µm diameter; hymenial tissue showing red-purplish crystal formation with potassium hydroxide. In crevices in dry bark of deciduous trees, known from a few scattered localities.
Refs: Smith et al. (2009), 838; Purvis et al. (1992), 562 (as S. nivea, given spore size too small); Wirth, Hauck & Schulz (2013), 2: 1038 (photo); Nordic Lichen Flora (1999) 1: 63, 90 (photo, as S. nivea); Holien & Tønsberg (2008), 147 (photo); Arup et al. (1997), 236 (photo, as S. nivea); Puntillo (1996), plate 37 (photo, as S. nivea).
This material was collected by accident, found in small quantity on examination of a bark-flake, and in some respects resembled S. amabilis, a Scandinavian species as yet unknown in Britain, although that is a somewhat larger species. Brian Coppins has confirmed that the material is S. pallida. Nevertheless, comparison of descriptions in different literature sources suggests that the circumscriptions of these species may merit more attention.
|On Sycamore (Acer pseudoplatanus), Kindrogan, Perthshire, March 2008|
|Photomicrograph of mazaedium, showing purple reaction with potassium hydroxide, Kindrogan, Perthshire, March 2008|
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Uploaded March 2010, last updated January 2016