Basionym. Lecanora confragosula Nyl. in Cromb., J. Linn. Soc., Bot. 15: 172 (1876). Type. SOUTH AFRICA. Western Cape, Table Mountain, Cape of Good Hope, 9-1874, A.E. Eaton s.n., Venus Transit Expedition (BM - lectotype, Mayrhofer (1984a); BM - isolectotype; H-NYL 28565 - isolectotype).
Rinodina filsoniiH. Mayrhofer, Beih. Nova Hedwigia 79: 517 (1984b). Type. AUSTRALIA. South Australia, summit of hill, ca. 2 km E Callington, 47 km SE Adelaide, ca. 750 m, 11. VIII. 1981, H. Mayrhofer 2755 (GZU - holotype!, isotype!).
Description.Thallus thin to thick, light to dark grey, areolate; areoles to 0.70-1.20 mm wide; surface matt, plane; margin determinate; prothallus absent or black, entire or fimbriate; vegetative propagules absent. Apothecia innate, becoming broadly attached, frequent, often contiguous, often single on areoles when fully grown, to 0.50-0.90 mm diam.; disc dark brown to black, sometimes coarsely pruinose, plane to slightly convex, sometimes half-spherical when overmature; thalline margin concolourous with thallus, entire, < 0.05 mm wide at first, later to 0.10 mm wide, persistent; excipular ring absent. Apothecial Anatomy. Thalline exciple (45-)60-100 µm wide laterally; cortex 10-15 µm wide; epinecral layer absent; crystals absent in cortex and medulla; cortical cells pigmented, to 4.5-6.0 µm wide; algal cells to 13.0-16.5 µm long; proper exciple hyaline, 5-10 µm wide laterally; expanding to 20-25 µm wide above, sometimes pigmented with Bagliettoana-green (also in areole walls); hypothecium hyaline, 60-100 µm deep, sometimes subtended by a stipe; hymenium 90-120 µm high, not inspersed; paraphyses filaments 2.5-3.5 µm wide, conglutinate, with apices to (3.5-)4.5-5.0 µm, apices not or very lightly capitate, immersed in a dispersed pigment forming a light olive-brown to darker red-brown epihymenium, sometimes with a surficial, yellow to orange insoluble pigment in gelatinous deposits on surface (sometimes also found in parts of medulla); ascus ca. 55 x19 µm. Ascospores 8/ascus, Type A development, Tunicata-type, (15.5-)19.0-20.0 (-23.5) x (9.0-)11.0-11.5(-13.5) µm, average l/b ratio 1.7-1.8, lumina initially Physcia-like, Pachysporaria-like at maturity; torus developing late; walls finely ornamented, overmature, collapsing spores with parallel, longitudinal wall folds. Pycnidia immersed; conidia 3.0-5.0 x 0.7-2.0 µm (Kaschik 2006).
Chemistry. Spot tests all negative; secondary substances not detected; the insoluble yellow-orange pigment is enhanced in KOH (Arceutina-yellow? Meyer and Printzen, 2000) and like the Bagliettoana-green is sporadic in occurrence (Kaschik 2006).
Substrate and Ecology. The three North American specimens were all found on natural sandstone outcrops in the grounds of the Santa Barbara Botanic Garden, one together with R. pacifica, and collected between 2003 and 2007. Elsewhere in the world it has also been recorded on quartzite, granite, basalt, dolerite and rhyolite (Kaschik 2006).
Distribution. This southern Californian locality is a first record for North America and the northern hemisphere. It is otherwise known from southern Africa, New Caledonia, Australia, including Tasmania and New Zealand (Kaschik 2006). The occurrence of R. confragosula in California is surprising but perhaps is no more remarkable than that of R. striatitunicata Matzer & H. Mayrhofer in Spain, another species with Tunicata-type spores with a similar southern hemisphere distribution (Kashik 2006). It is speculated that these species may have rafted on microcontinents into accreted terrains from the eastern (Pacifica) and northern margins of Gondwanaland, respectively (Galloway 1989, Nur and Ben-Avraham 1983).
Notes.Rinodina confragosula is the only North American species with Tunicata-type spores and is therefore difficult to confuse with other species. It is remarkable that this southern hemisphere species occurs in North America and the record might be viewed with some scepticism for this reason. However, it is impossible to separate from the Australian and New Zealand specimens (GZU) with which it was compared and includes both of the relatively rare Bagliettoana-green and yellow-orange pigments which occur sporadically in this species. Its substrate rock in the grounds of the Santa Barbara Botanical Gardens is in situ (Tucker personal communication) and there is no reason to think that the species may have been introduced on exotic rock for landscaping purposes.
The spores may indicate a relationship with R. striatitunicata, which as its name suggests, has striate wall ornamentation. In R. confragosula, very overmature spores are characterized by their walls collapsing in elongate folds which may imply a similar underlying wall structure to that influencing the striate ornamentation in the former species. Rinodina tunicata H. Mayrhofer & Poelt shares this characteristic but not R. calcarea (Arnold) Arnold, a species with Mediterranean and southern European distributions, respectively. Rinodina confragosula is separated from all the above species by the presence of a torus, which is also found in the related R. argentiniana according to Mayrhofer (1984b), a species with larger spores. The group probably has a very ancient origin, with representative species possessing Tunicata-type spores in the northern and southern hemispheres.
Very rarely, apparent B type spore development is seen in R. confragosula. However, such immature spores have not been observed to ever become septate, they develop into aberrant single celled spores. Similar states have been observed in some other spore types. The Tunicata-type spores of R. calcarea, on the other hand, show Type A or B spore development as previously reported by Giralt (2001).
The structure of the Tunicata-type spore has been described by Poelt and Mayrhofer (1979) based on light microscopy and Nordin (1997) based on electron microscopy studies of R. tunicata. Under pressure, the proper wall of this species fractures away from the endospore wall (Poelt and Mayrhofer 1979), using the terminology of Nordin. A similar structure is seen in R. confragosula except for a double outermost layer, which may represent the perispore visually separated from the proper wall by the intermediary layer swollen in KOH.
Specimens examined. U.S.A. CALIFORNIA. Santa Barbara Co., Santa Barbara Botanic Garden, Mission Canyon, Santa Barbara, on sandstone, S.C. Tucker 37872, 38523a, 39000 (SBBG).