Type. [U.S.A.] OREGON. Upon bark, s.d. E. Hall s.n. (FH ‑ lectotype here designated); CALIFORNIA. Upon redwood and oak, s.d. H.N. Bolander s.n. (FH ‑ syntype!).
Lecanora exigua f. pruinosa Merrill, Ottawa Naturalist 27: 118 (1913). Type. [CANADA.] BRITISH COLUMBIA. Vancouver Island, s.d. J. Macoun s.n. (CANL ‑ lectotype designated in Sheard 2010).
Exsiccatae. Krypt. Vind. 1560 (BM, NY); Macoun Can. Lich. 145, 194 (MICH, NY as Buellia parasema var. triphragmioides).
Description.Thallus thin, grey or more usually ochraceous to brownish, continuous or becoming rimose, rarely areolate; areoles ca. to 0.80 mm wide; surface plane, matt; margin determinate; prothallus thin, entire, dark brown; vegetative propagules absent. Apothecia broadly attached, frequent, rarely contiguous, to (0.35-)0.70-0.90 mm in diam.; disc dark brown to black, typically becoming pruinose, plane at first, becoming convex; thalline margin lacking; proper margin biatorine, concolourous with disc, 0.05-0.10 mm wide, entire, sometimes becoming excluded. ApothecialAnatomy. Thalline exciple lacking; proper exciple (50-)70-100 µm wide, pigmented light brown in part; algal cells occasionally found in base of exciple; hymenium 80-110(-140) µm high, not inspersed; paraphyses 1.5-2.0 µm wide, conglutinate, sometimes with oil cells, with apices to 2.5-3.0 µm wide, lightly pigmented, darkly so in apothecia with black discs, immersed in dispersed pigment, forming a red‑brown epihymenium, crystals on surface; hypothecium hyaline, 65-105 µm deep; asci clavate, 60-80 x 17-24 µm. Ascospores 8/ascus, Type A development; Physcia- to Physconia-type, (17.0-) 20.5-22.0(-25.0) x (8.0-)9.5-10.5(-12.0) µm, average l/b ratio 2.0-2.3, lumina angular at first, quickly becoming rounded, some becoming thin walled at apices; torus narrow, well developed in some spores; walls ornamented. Pycnidia not seen.
Chemistry. Spot tests all negative; secondary metabolites, zeorin, variolaric acid.
Substrate and Ecology. Mostly recorded from deciduous trees but also on conifers. Collected on Alnus rhombifolia, A. rubra, Acer macrophyllum, Amelanchier alnifolia, Cornus nuttallii, Crataegus, Fraxinus, Holodiscus discolor, Juniperus scopulorum, Quercus agrifolia, Q. chrysoleptus, Q. garryana, Q. kellogii, Q. tomentella, Pseudotsuga menziesii and Thuja plicata from sea level in the north to 1,675 m in the southernmost part of its range. Collected once with Rinodina bolanderi.
Distribution. A North American endemic with an oceanic distribution from British Columbia, southwards to Southern California. Mainly in coastal areas and the Coastal Ranges but also in the northern Sierra Nevada, with outliers in Haida Gwaii (Queen Charlotte Islands) and Idaho.
Notes. The thin, continuous to rimose, ochraceous or brownish thallus, and large, biatorine apothecia with pruinose discs and Physcia-Physconia-type spores make R. hallii distinct among North American corticolous Rinodina species. Rinodina hallii possibly might be mistaken for R. herrei in coastal areas since the discs of this species also become convex and the margins excluded. The latter species, however, has smaller, Teichophila-type spores which are inflated at the septum. It may be related to R. trevisanii which has a similar thallus morphology and chemistry, and also develops biatorine apothecia. However, R. trevisanii is distinguished by its mostly smaller apothecia, absence of pruinose discs, and significantly smaller, Physconia-type spores which have relatively persistent lumina canals during development.
Other notable features of R. hallii are the conglutinate paraphyses, the narrow apical cells of the paraphyses and the nature of the biatorine margin. The resulting gelatinous hymenium seems to attract invertebrates and it is quite common to find the apothecia (and thallus) eroded by grazing. The same phenomenon is also observed in other species with gelatinous hymenia such as the eastern R. ascociscana and R. subminuta. The paraphyses are unusual in the narrowness of their filaments and apical cells, and in the very limited amount of pigment deposited within the apical cells. Oxalate crystals on the surface of the epihymenium are the basis of the pruinose discs. These crystals typically extend around the edge of the hymenium and below it, within the proper margin. They may also be abundant in the thallus cortex.
The biatorine margin may frequently be seen to include pigmented layers. The outermost layer may be pigmented or not. It is surmised that new plectenchyma is produced at the periphery of the proper exciple as the apothecium grows. This becomes pigmented at the surface during the growing season and the process is repeated the following season forming bands of pigment in the margin. As the apothecium enlarges laterally the plectenchyma is subsumed and compressed below the apothecium, the pigmented layers losing their definition in this region.
Specimens examined. CANADA. BRITISH COLUMBIA. 5 km N Sidney, W.J. Noble 6465 (UBC); Comox, 1893, J. Macoun (FH, MICH, NY, US); 1915, J. Macoun (CANL); Denman Island, W.J. Noble 2450d, 2627; Gabriola Island, W.J. Noble 3014a; Genoa Bay, W.J. Noble 4841b (all UBC); Haida Gwaii (Queen Charlotte Islands), T. Tønsberg 32406 (BG); Sandspit, I.M. Brodo 10087 (CANL, MSC, WIS); 17163 (CANL); Hornby Island, W.J. Noble 2720b; Mayne Island, W.J. Noble 1937b (both UBC); 1914, J. Macoun (CANL); J. Macoun 350 (FH); Mount David, W.J. Noble 1427 (UBC); Mount Warburton, W.J. Noble 1501B (SASK); Saturna Island, W.J. Noble 1431, 1499b (UBC); Sidney, 1911, 1912, 1914, 1915, 1916, J. Macoun (FH); Sidney, 1913, J. Macoun (CANL). U.S.A. CALIFORNIA. Hidden Villa Canyon, A.C. Herre 548 (FH, MIN, US); 1904, A.C. Herre (FH, UC, US); Humboldt Co., E Berry Summit, 1972, L.H. Pike (SASK); Kneeland, H.E. Parks 3697A (UC); Los Angeles Co., Martin's Camp, 1896, H.E. Hasse (NY); San Clemente Island, W.A. Weber 42902 (COLO); S. Junak 886h; C.C. Bratt 9919 (both SBBG); San Gabriel Mountains, H.E. Hasse 566 (NY, US); 1897, H.E. Hasse (ABSL, FH, MIN); 1903, H.E. Hasse (US); Santa Monica Mountains, 1899, H.E. Hasse (H); Marin Co., Mount Tamalpais, S.C. Tucker 37566 (SBBG); Mariposa Co., Yosemite Valley, H.N. Bolander (US); Mendocino Co., Anderson Valley, 1888, H.N. Bolander (PH); Boonville, H.N. Bolander 239 (US); Monterey Co., Hastings Natural History State Reservation, B.D. Ryan 27113 (ASU); C.C. Bratt 9290 (SBBG); 1943, J.M. Linsdale (UC); Nacimiento, C.C. Bratt 6207 (SBBG); P. van den Boom 29460; Pfeiffer Big Sur State Park, P. van den Boom 29426 (both personal herb.); Napa Co., A. Blythe 5379 (LSU); Nevada Co., Grass Valley, 1951, A. Blythe (SBBG); Plumas Co., Quincey, S.C. Tucker 6489B (SBBG); San Benito Co., Bear Gulch, 1904, A.C. Herre (FH, UC); San Luis Obispo Co., I. Tavares 1371 (UC); 10 mi E San Simeon, T.H. Nash, 8142 (ASU); San Mateo Co., Black Mountain, 1903, A.C. Herre (NY); 1904, A.C. Herre (FH, NY); A.C. Herre 453 (MIN); Devil’s Canyon, S. Shushan 14559 (COLO); Mud Lakes, 1942, M. Doty (NY); Paso Robles, 1897, Barber (FH); 10 mi W Saratoga, I.M. Brodo 20423a (CANL); Searsville Lake, S. Shushan 14671 (COLO); Santa Barbara Co., Santa Cruz Island, C.C. Bratt 2079 (SBBG); T.H. Nash 32515 (ASU); Santa Clara Co., Los Gatos, A.C. Herre (BM, FH, NY, US); Saratogo Gap, L. Sigal 169 (ASU); Santa Cruz Co., above Glenwood, 1938, A.C. Herre (UPS, WIS); Boulder Creek, V.F. Hesse (UC); Castle Rock, S. Shushan 14750 (COLO, UPS); Castle Rock, 1945, A.C. Herre (UC); Solano Co., Blue Ridge Summit, S.C. Tucker 37466 (SBBG); Sonoma Co., Glen Ellen, 1946, A.C. Herre (UPS); Tehema Co., Junction Hwys. 32 & 36, 1978, A.W. Ratcliff (SBBG). IDAHO. Shoshone Co., 3 km W Avery, C. Bjorke 10238a (Goward personal herb.). OREGON. Benton Co., 10 mi NW Corvallis, W.A. Weber 1825 (COLO); Corvallis, B. McCune 17994 (SASK); B. McCune 25202; Paul Dunn Forest, B. McCune 20069 (both personal herb.); Clackamas Co., Mount Hood Nat. Forest, W.A. Weber 33500 (COLO); Clatsop Co., Ecola State Park, S.C. Tucker 15109 (LSU); Hood River Co., Mount Hood (CANL); Josephine Co., Rogue River Canyon, B. McCune 24555 (personal herb.); Lane Co., Long Tom River, P. Neitlich 762 (McCune personal herb.); Linn Co., Halsey, L.H. Pike 1318 (SASK); Horse Rock Ridge, B. McCune 25808 (personal herb.); Multnomah Co., Sauvies Island, 1882, T. Howell; Wasco Co., Cascade Locks, 1885, W.N. Suksdorf (both PH); Washington Co., Forest Grove, 1895 (NY); Yamhill Co., Gopher Valley, 1880, R.W. Summers (PH); Parret Mountain, S.E. Carpenter 565 (MICH). WASHINGTON. Clallam Co., Cape Alava, T. Tønsberg 27024 (BG); Cape Flattery, 1935, A.H. Smith (FH); A.H. Smith 13141 (UC); Waadah Island, T. Tønsberg, 25860 (BG); Grays Harbor Co., Westport, 1907, 1908, A.S. Foster (FH); Jefferson Co., Quinault, I.M. Brodo 15437 (CANL); Pacific Co., E Willapa Bay, T. Tønsberg 33323 (BG); Long Island, B. McCune 19688 (personal herb.); San Juan Co., Camp Orkila, T. Tønsberg 26739; Orcas Island, T. Tønsberg 26724; San Juan Island, T. Tønsberg 26724, 26818; Skamania Co., Carson, T. Tønsberg 21069b (all BG); Whatcom Co., SE Bellingham, B.D. Ryan 4596 (SASK).
Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: crustose, thin, continuous becoming rimose, rarely areolate, areoles up to c. 0.8 mm wide, plane surface: gray or more usually ochraceous to pale brown, dull; margin: determinate; prothallus: thin, entire, dark brown; vegetative propagules: absent Apothecia: adnate, frequent, rarely contiguous, up to (0.35-)0.7-0.9 mm in diam. disc: dark brown to black, typically becoming pruinose, plane at first, becoming convex thalline margin: lacking; proper margin: biatorine, concolorous with disc, 0.05-0.1 mm wide, entire, sometimes becoming excluded thalline exciple: lacking proper exciple: (50-)70-100 µm wide, pigmented light brown in part; algal cells: occasionally found in base of exciple hymenium: 80-110(-140) µm tall; paraphyses: 1.5-2 µm wide, conglutinate, with apices up to 2.5-3 µm wide, hardly pigmented, immersed in dispersed pigment, forming a red-brown epihymenium, crystals on surface; hypothecium: hyaline, 65-105 µm thick asci: clavate, 60-80 x 17-24 µm, 8-spored ascospores: brown, 1-septate, narrowly ellipsoid, type A development; Physcia-type, (17-)20.5-22(-25) x (8-)9.5-10.5(-12) µm, lumina angular at first, quickly becoming rounded, apical walls mostly remaining thick; torus: narrow, well developed in some spores; walls: ornamented Pycnidia: not seen Spot tests: all negative Secondary metabolites: zeorin, ± variolaric acid. Substrate and ecology: mostly on deciduous trees (Quercus agrifolia and Q. tomentella) but also on conifers World distribution: a North American endemic with an oceanic distribution from the Queen Charlotte Islands, British Columbia, to southern California Sonoran distribution: Santa Cruz Island, San Clemente Island and San Gabriel Mountains, at elevations of 395-1675 m. Notes: The thin, continuous to rimose, ochraceous or brownish thallus, and the large, biatorine apothecia with pruinose discs make R. hallii distinct among North American Rinodina species on bark. It may be related to R. trevisanii that also has a similar thallus morphology and chemistry, and also develops biatorine apothecia. Rinodina trevisanii is distinguished by its mostly smaller apothecia, absence of pruinose discs, and significantly smaller spores belonging to the Physconia-type. There are no recent mainland records from the study area.