Basionym. Lecanora aspersa Borrer in Hook., Suppl. Engl. Bot. 2: tab. 2728 (1832). Type. ENGLAND. Sussex Co., on flints, s.d. W. Borrer s.n. [ex herb. Salwey] (BM - lectotype (Laundon 1986) not seen). Rinodina fatiscens (Th. Fr.) Vain., Meddeland. Soc. Fauna Fl. Fenn. 47: 8 (1921). Type. SWEDEN. Uppsala, Halmbyboda, 12 July 1852, Th. M. Fries s.n. (UPS - lectotype (Mayrhofer & Poelt 1979) not seen).
Selected References. Mayrhofer & Poelt (1979 as R. fatiscens), Mayrhofer (1984a as R. fatiscens), Laundon (1986), Fox & Purvis (1992), Giralt (2001), Mayrhofer & Moberg (2002 p. 100).
Description.Thallus thin, dark grey, areolate; areoles discrete and ± circular, or contiguous and angular, to ca. 0.40 mm wide; surface plane to slightly convex (subverrucose), matt; margin determinate; prothallus black, fimbriate or entire; vegetative propagules present; soredia; farinose, light grey-green on larger areoles, ca. 0.55 mm wide; soralia occupying most of areoles, well delimited, flat with slightly raised margins, ca. 0.50 mm in diam. Apothecia not recorded in North America, rare in Europe, broadly or narrowly attached, to ca. 1.0 mm in diam.; disc brown, paler when wet, plane; thalline margin concolourous with thallus. Apothecial Anatomy. Hypothecium hyaline, to 100 µm deep; hymenium 80-100 µm high, not inspersed; epihymenium brown. Ascospores 8/ascus, developmental type A, Pachysporaria-type, 15-20 x 10-13 µm; torus present (according to Mayrhofer and Moberg, 2002). Pycnidia not seen.
Chemistry. Spot tests, thallus K+ yellow, C-, P+ faint yellow, soralia K-, C+ red, P-; secondary metabolites, atranorin in cortex, gyrophoric acid in medulla, with lecanoric and orsellinic, umbilicaric, ovoic and 5-O-methylhiasic acids (Mayrhofer & Moberg 2002).
Substrate and Ecology. Saxicolous, on siliceous rocks in moist, marine environment, partially shaded by Arbutus menziesii.
Distribution.Rinodina aspersa is only known from San Juan Islands, Washington in North America (Glew 1999). A rare species distributed in temperate Europe, south to Portugal and Mediterranean islands (Mayrhofer and Moberg, 2002).
Notes. The sorediate R. aspersa is recognized by its characteristic chemistry which is identical to that of the nonsorediate European species R. atrocinerea (Hook.) Körb. Laundon (1986) provides an extensive discussion of the species which he regards as a secondary species derived from R. atrocinerea. The fertile form, previously known as R. fatiscens, has a scattered distribution in Europe (Mayrhofer 1984a, Giralt 2001), is less frequent but very similar to R. aspersa. The recent discovery of R. aspersa in North America conforms with that of other secondary species which typically have a wider distribution than their primary species and shows a disjunct distribution similar to the corticolous, vegetatively reproducing species discussed by Sheard (1995). Rinodina aspersa is one of only two saxicolous, sorediate species in North America, the other being R. stictica which is mostly corticolous.
The spores of R. atrocinerea belong to the Pachysporaria-type I possessing subpolygonal lumina during their development. Although they are smaller than in other species with this spore type reported in this monograph they are similar in size to those of the corticolous R. roboris commented on earlier. Spores of R. aspersa have not been studied but their similarity in size and structure (Fox & Purvis 1992, Mayrhofer & Moberg 2002) and the identical, complex chemistry of R. atrocinerea suggests that it will prove to possess Pachysporaria-type I spores also.
Specimen examined. U.S.A. WASHINGTON. San Juan Co., Friday Harbour Marine Laboratory, K.A. Glew 980918-57 (WTU).