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Family: Physciaceae
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MB#404246 Basionym. Rinodina mniaraea $ calcigena Th. Fr., Kongl. Vetensk. Acad. Handl. 7(2): 25 (1867). Rinodina occidentalis Lynge, Meddel. Grønland 118: 188 (1937). Description. Thallus grey, ochraceous or grey-brown, inconspicuous, present only around base of apothecia or as thin, scattered areoles on substrate, ca. 0.30 mm diam., more rarely thick, areoles to 0.55‑1.20 mm wide; surface plane or verrucose, shining or matt; margin usually indeterminate; prothallus absent; vegetative propagules absent; Apothecia erumpent at first, broadly attached, sometimes becoming narrowly attached, frequent, single or 2‑4 per areole, sometimes angular by compression, to 0.50‑0.90 mm diam.; disc black, plane becoming convex, sometimes pruinose (best seen when wet), sometimes fissured when half-globose; thalline margin often lighter than thallus at first due to flaking epinecral layer, typically becoming darker brown than thallus, 0.05‑0.10 mm wide, entire, sometimes becoming excluded; excipular ring absent or confluent. Apothecial Anatomy. Thalline exciple hyaline, 60‑115 µm wide; cortex 10‑25 µm wide; epinecral layer 5‑20 µm wide; crystals absent in cortex and medulla; cortical cells pigmented at periphery, to 4.5‑7.5 µm wide; algal cells to 9.0‑20.0 µm long; thalline exciple expanded to ca. 120 µm wide when apothecia narrowly attached; proper exciple hyaline, 10‑20 µm wide laterally, expanding to 15‑50 µm wide above; hypothecium hyaline, 40‑120 µm deep, often developing a stipe; hymenium heavily inspersed, 60‑110 µm high; paraphyses 2.0‑3.5 µm wide, not conglutinate, apices expanded to 4.0‑6.5 µm, pigmented dark brown, forming a dark brown, sometimes reddish brown epihymenium; asci 40‑75 x 18‑25 µm. Ascospores 8/ascus, developmental type A, Bischoffii‑type, (15.0‑)19.0‑20.0(‑23.5) x (9.0‑)11.0‑11.5(‑13.0) µm, average l/b ratio 1.6-1.8, sometimes laterally inflated at first, elongate canal sometimes evident in young spores, lumina mostly retaining a broad canal at maturity; torus absent; walls not ornamented, darkly pigmented, pigmented band rarely evident around septum at maturity but immature spores may possess very broad pigmented bands, sometimes persisting to maturity, spores often becoming parallel sided, rarely constricted. Pycnidia fully immersed in thallus, only visible when moist; conidiophores type VI; conidia bacilliform, 5.5-7.0 x 1.0 µm. Chemistry. Spot tests all negative; secondary metabolites, trace of zeorin demonstrated in one specimen. Substrate and Ecology. Rinodina calcigena is a species of calcareous rocks and shale in the Arctic and the Rocky Mountains (1,220-2 590 m). Distribution. This species belongs to the oro-arctic element and is known throughout the Arctic and from the Rocky mountains. It also occurs in Scandinavia (Mayrhofer & Moberg 2002), Siberia (Mayrhofer 1984), West Greenland (Alstrup 1986), and from East Greenland (Thomson 1997). The species has previously been recorded from Greenland as R. castanomelodes by Hansen (1984). The records from Utah may belong to R. guzzinii but have not be available for reinvestigation. Notes. Rinodina calcigena is related to R. bischoffii by spore type and distinguished from this species by its longer spores, longer conidia and typically very symmetrical apothecia with brown, thalline margins at maturity. It has an extremely variable thallus morphology like so many arctic lichens. The thallus may vary from being limited to the base of the apothecia, through scattered verrucae, to being well developed and areolate. The thallus colour is typically a shade of brown but the pigment is often partially obscured by an epinecral layer. However, the thallus is frequently eroded and it is then ochraceous grey or even light grey. The apothecia are typically erumpent at first with light coloured margins due to flaking of the epinecral layer. Later the margin becomes darker than the thallus. The disc is plane at first, sometimes becoming convex and causing the thalline margin to become excluded. The spore size and structure of R. calcigena are similar to R. guzzinii which could lead to misidentification. For a detailed comparison with R. guzzinii refer to that species. Further details may be found in Mayrhofer and Sheard (1988). Mayrhofer and Moberg (2002) refer the spores of R. calcigena to the Physconia-type and then state that they are in some respects intermediate between the Bischoffii- and Physconia-types. It is true that both these types have unthickened apical walls and the spores of R. calcigena have unusually narrow lumina canals during development for the Bischoffii-type. However, the spores never show apical thickening during development, a characteristic of the Physconia-type. The spores are also quite darkly pigmented and rarely can be observed to possess less darkly pigmented apices both during development and at maturity. This suggests that they should be regarded as belonging to the Bischoffii-type, possessing unusually broad pigmented bands. Other characters such as hymenial inspersion and lack of a dispersed red-brown pigment in the epihymenium also suggest that R. calcigena is related to the R. bischoffii group of species rather than those associated with Physconia-type spores. Specimens examined. CANADA. ALBERTA. 2 mi S Pincher Creek, B.D. Ryan 13950 (ASU); Jasper Nat. Park, G.W. Scotter 7750; Queen Elizabeth Range, G.W. Scotter 7799; Waterton, 1978, D. McAllister; Wilcox Ridge, G.W. Scotter 7684 (all CANL); BRITISH COLUMBIA. 3 km E Rock Lake, E. Lay 1599 (personal herb.). NUNAVUT. Axel Hieberg Island, G.W. Scotter 46426; Devon Island, P. Barrett 318a ( both WIS); Erebus Bay, A. Innes‑Taylor 124; Eureka, G.W. Scotter 46461; Polar Bear Pass, H.L. Dickson 2298; I.M. Brodo 19264B, 19302B; Pond Inlet, M.E. Hale 862; Southampton Island, 1970, G.R. Parker (all CANL); Banks Island, Thomsen River, W.A. Gould 939 (MIN); Devon Island, Truelove Lowland, D.H. Richardson 67 (WIS); Ellesmere Island, Fosheim Peninsula, 1990, F. Brodo; Ellesmere Island, Svedrup Pass, 1986, P.F. Maycock. MANITOBA. Churchill, J.W. Thomson 3727, 3855 (all CANL); 3855 (US, WIS). NORTHWEST TERRITORIES. Artillery Lake, J.W. Thomson 12331 (PMAE, US, WIS). QUEBEC. Gaspé-Nord Co., Mont St. Pierre, R. Gauthier 2623 (CANL). GREENLAND. Disko Island, Asuk, P. Gelting 18842A, B, C, D, E; 18853B, D, E (all C); Marmorilik, Umanak, 1983, J. Poelt (GZU); Nugssuaq Peninsula 1871, Th. M. Fries (C, FH, O, S); Sondre Stromfjord, 1979, V. Alstrup (CANL). U.S.A. ALASKA. Pitmegea River, J.W. Thomson 10587b; Umiat, J.W. Thomson 10252 (both WIS). UTAH. Moffat, Dinosaur Nat. Mon., 1991, C. Newberry; Wasatch, E Heber City, C. Newberry 1078 (both BRY). Selected References. Mayrhofer & Poelt (1979), Mayrhofer (1984a), Mayrhofer & Sheard (1988), Thomson (1997), Mayrhofer & Moberg (2002, p. 101). Thompson, J., 1997. American Arctic Lichens: The Microlichens. Thallus brown or gray where eroded, scant, only around base of apothecia or of scattered granules, 0.3 mm diameter, rarely thicker, verruciform or areolate, shining or dull. Apothecia 1-3 per areola, at first innate and erumpent, becoming sessile, to 0.9 mm broad; margin either of same color as disk or as thallus; thalloid exciple cellular and with an epicortex; proper exciple 10-20 μm, broadening to 10-50 μm above; disk black, flat becoming convex, sometimes pruinose; hypothecium hyaline, developing a stipe; epihymenium dark brown; hymenium inspersed; paraphyses 2.0-3.5 μm, tips 4-6.5 μm and very dark; asci clavate; spores of bischoffii-type, that is, with outer walls at septum invaginated and darkened, forming a lightly pigmented band around center of spore, a porus also being present, 16-24 x 9.5-13 μm. This species grows on calcareous rocks. It is known from Scandinavia, Spitzbergen, Novaya Zemlya, Greenland, Alaska, and arctic Canada, south to Colorado. It thus appears to be circumpolar arctic. The closely related Rinodina castanomela (Nyl.) Arnold, which differs from this only in having a thick, areolate, and marginally lobed thallus, has been reported from Disko Island, Greenland, by Hansen (1984, p. 312). |