Description.Thallus thin, dark grey to brownish grey, rimose, becoming rimose-areolate; areoles ca. 0.20 mm wide at margin, to 0.40-0.70 mm wide in centre; surface plane to slightly rugose, matt; margin determinate; prothallus lacking; vegetative propagules absent. Apothecia erumpent, remaining innate or becoming broadly attached, scattered or contiguous, to 0.40-0.50 mm in diam.; disc dark brown to black, plane or slightly convex; thalline margin absent, or concolourous with thallus, sometimes becoming pigmented, entire, 0.05-0.10 mm wide, persistent; excipular ring absent or raised. Apothecial Anatomy. Thalline exciple absent, or 50-60 µm wide; cortex absent or 5-10 µm wide; epinecral layer absent or 5-10 µm wide; crystals absent in cortex and medulla; cortical cells to 4.0-6.0 µm wide, pigmented or not; algal cells to 9.0-15.5 µm long; thalline exciple not expanded below; cortex sometimes expanded to 25-30 µm deep, hyphae intricate; proper exciple hyaline, 5-10 µm wide laterally, expanding to 15-20 µm wide above; hypothecium hyaline, (30-)50-80 µm deep; hymenium 65-90 µm high, not inspersed; paraphyses 2.0-2.5 µm wide, conglutinate, apices to 3.5-5.0 µm wide, forming a light to dark brown epihymenium; asci 45-55 x 13-18 µm. Ascospores 8/ascus, Type A or B development, Dirinaria-type, (12.0-) 15.0-16.5(-19.0) x (6.5-)7.5-8.0(-9.5) µm, average l/b ratio 1.9-2.0, often slightly inflated at septum, more so in KOH, lumina angular (Physcia-like) at first; torus absent; walls lightly ornamented or not. Pycnidia with conidia bacilliform, 3.0-3.5 x 1.0 µm.
Chemistry. Spot tests all negative; secondary metabolites not detected (Giralt 2001).
Substrate and Ecology. Recorded on Acer saccharum, Beaucarnea longifolia, Pseudotsuga menziesii, Rhamnus purshiana and Sorbus. The specimen on Beaucarnea was collected on the upper trunk of a windfall. Rinodina oleae has been collected with R. albertana, R. aurantiaca, R. disjuncta, R. efflorescens, R. laevigata, R. orculata, R. pachysperma, R. populicola and R. subminuta, mostly species of high rainfall or otherwise humid environments, at elevations of 675-2,500 m in the west.
Distribution. Scattered and rare in North America, from Michigan to California. Common and widely distributed in southern Europe, often in eutrophic habitats such as roadside trees (Giralt 2001).
Notes. This species is characterized by its relatively small, Dirinaria-type spores, and innate to broadly attached apothecia. Giralt (2001) describes the thalli as “covering wide areas” but under habitat suggests that it “usually forms small thalli” which agrees with North American observations. The close relationship of R. oleae with R. gennarii has been much discussed (Giralt & Mayrhofer 1995, Trinkaus et al. 1999, Giralt 2001) and is supported by molecular data (Helms et al. 2003, Kaschik 2006). However, it has a very different habit to lignicolous specimens of R. gennarii found in maritime habitats and this author prefers to keep the two species separate at the present time. Supporting this conclusion are the typically more narrowly ellipsoid spores, smaller conidia and the smaller apical cells of the paraphyses of R. oleae. More detailed studies are required on maritime, lignicolous collections of R. gennarii and corticolous R. oleae when more specimens become available.
Specimens examined. U.S.A. CALIFORNIA. Santa Barbara Co., Goleta Beach, S.C. Tucker 36561; Montecito, S.C. Tucker 34424 (both SBBG). IDAHO. Idaho Co., Lochsa River Valley, T. Tønsberg 26587, 26593b (BG). MICHIGAN. Alger Co., 4 mi WSW Grand Marais Pictured Rocks Nat. Lakeshore, C.M. Wetmore 58766. MINNESOTA. Koochiching Co., Black Bay, C.M. Wetmore 37322; St. Louis Co., 3.5 mi E Idington, C.M. Wetmore 87297; Voyageurs Nat. Park, C.M. Wetmore 33122 (all MIN). NEW MEXICO. Otero Co., Cloudcroft, T.H. Nash 7342 (ASU).
Selected References. Magnusson (1947a), Giralt & Mayrhofer (1995), Giralt et al. (1997), Giralt (2001 Plate XVII: E), Kaschik (2006 Fig. 50 including R. gennarii).