Biatora alnetorum S. Ekman & Tonsberg

Ekman, Stefan & Tonsberg, Tor, 2019, Biatoraalnetorum (Ramalinaceae, Lecanorales), a new lichen species from western North America, MycoKeys 48, pp. 55-65 : 58-59

Biatora alnetorum S. Ekman & Tonsberg sp. nov. Figs 2, 3, 4

Diagnosis.

Similar to Biatora pallens (Kullh.) Printzen in having 3-septate ascospores and crystals in the exciple, but differs from that species primarily by the sorediate thallus, the production of atranorin in the thallus and proper exciple and in sometimes producing up to 7-septate ascospores.

Types.

U.S.A. Washington, Cowlitz Co., 7-8 km SW of summit of Mount St. Helens, E of Goat Mtn, NE of Goat Marsh Lake, N of Coldspring Creek, the W-facing slope W of gravel Rd FR 8123, 46°10'N, 122°17'W, elev. 900-1000 m, corticolous on Alnus alnobetula subsp. sinuata, 8 Aug 1996, T. Tønsberg 24071 (holotype: BG-L-101921; isotypes: BM, CANL, FR, NY, O, OSC, TRH, UPS, UBC, WTU).

Etymology.

The epithet, alnetorum, means 'of the alder stands’ and is a reference to the fact that Biatora alnetorum prefers thickets dominated by Alnus alnobetula subsp. sinuata.

Description.

Thallus crustose, thin, continuous, finely cracked, whitish, forming ± convex pustules from which soralia develop. Pustules greenish (with no hint of yellow; pale grey in the herbarium), glossy, mostly discrete, firm, rounded or rarely ± ellipsoid in outline, 0.08-0.32 mm diam. when rounded and 0.12-0.60 × 0.10-0.36 mm diam. when ellipsoid. Soralia forming by disintegration of pustules into convex aggregations of yellowish grass-green (pale straw in the herbarium) and loosely arranged soredia, finally eroding into ± empty and shallow pits. Soredia mostly ellipsoid, rarely globose, strikingly similar in shape and size, firm (not easily disintegrating in squash preparations), 22 –47– 79 µm long (s = 14, n = 30) and 19 –32– 46 µm wide (s = 8, n = 30). Prothallus lacking. Photobiont unicellular, chlorococcoid, globose to (irregularly) ellipsoid, 7.5-12.5 µm long.

Apothecia absent or sparse, sometimes abundant, biatorine, 0.3 –0.5– 0.9 mm diam. (s = 0.1, n = 50), at first flat, later moderately convex, epruinose or thinly pruinose on edge. Disc pale pink (or pale yellowish with age in the herbarium). Margin pale pink to almost white, concolorous with disc or slightly paler, thick, distinct, raised above disc in young apothecia, soon level with the disc, persistent.

Proper exciple laterally 54-68 µm thick, with abundant minute crystals (<1 µm diam.) that are soluble in KOH, colourless or diffusely pale orange-yellow, prosoplechtenchymatous, composed of radiating hyphae that branch in the inner but not outer part of the exciple, with gelatinised cell walls; cell lumina narrowly cylindrical, 0.7-0.8 µm wide (swelling in KOH); terminal cells not swollen or moderately swollen to 2 µm. Hypothecium colourless to pale orange-yellow, without crystals. Hymenium 41 –56– 63 µm thick (s = 6, n = 25), colourless or diffusely pale orange-yellow, usually without crystals, rarely with a thin and uneven layer of crystals at the surface. Paraphyses 1.6 –2.1– 2.8 µm wide in mid-hymenium (s = 0.3, n = 25), unbranched or moderately branched in upper part, sometimes sparingly anastomosed in lower part; apices not swollen to ± clavate, 1.6 –2.8– 4.7 µm wide (s = 0.6, n = 50), without internal pigment. Asci clavate, 8-spored; young spore mass forming a wide and bluntly conical ocular chamber, apex above young spore mass staining blue in IKI except for a pale blue and narrowly conical axial body surrounded by a dark blue zone (i.e. approximately of Biatora -type sensu Hafellner (1984)). Ascospores colourless, without perispore or ornamentation, bacilliform to short-acicular, straight or slightly curved to shallowly sigmoid, sometimes coiled in ascus, 17 –30– 53 µm long (s = 6, n = 50), 1.8 –2.4– 3.6 µm wide (s = 0.3, n = 50), 7.0 –12.9– 22.0 times as long as wide (s = 2.9, n = 50), mostly with 3 but sometimes with up to 7 septa.

Pycnidia not seen.

Chemistry: Large amounts of atranorin in thallus and apothecia. Thallus, soralia and proper exciple K+ yellow.

Pigments: No pigments or small amounts of Rubella-orange ( Meyer and Printzen 2000) in proper exciple, hypothecium and/or hymenium.

Distribution and ecology.

Biatora alnetorum is known from the Pacific Northwest of North America in Washington and Alaska (U.S.A.) and British Columbia (Canada). Its vertical distribution ranges from 620 to 1450 m a.s.l. It occurs in openings in humid old-growth coniferous forest and Alnus woodlands and in the alpine scrub zone. B. alnetorum inhabits smooth bark of trunks or, occasionally, branches. The phorophyte is almost exclusively Alnus alnobetula subsp. sinuata (also known as Alnus viridis subsp. sinuata), except for a single record on Alnus rubra . Other lichens occurring together with B. alnetorum include (on Alnus alnobetula ) Caloplaca sorocarpa (Vain.) Zahlbr., Biatora flavopunctata ( Tønsberg) Hinter. & Printzen, B. toensbergii Holien & Printzen, B. vacciniicola ( Tønsberg) Printzen and Pertusaria carneopallida (Nyl.) Anzi ex Nyl. and (on Alnus rubra ) Parmeliopsis hyperopta (Ach.) Arnold, Japewia subaurifera Muhr & Tønsberg, and Phlyctis speirea G. Merr.

Remarks.

Part of the type collection contains the lichenicolous fungus Sclerococcum toensbergii Diederich ( Diederich and van den Boom 2017). This fungus was, according to Diederich and van den Boom (2017) and Diederich et al. (2018), previously known to occur on Megalaria pulverea (Borrer) Hafellner & E. Schreiner ( Ramalinaceae ) and Pertusaria carneopallida (Nyl.) Anzi ex Nyl. ( Pertusariaceae ). Biatora alnetorum is reported here as a new host for this fungus.

Additional specimens examined.

Canada. British Columbia: N of Vancouver, Garibaldi Park, N of Wedgemount Creek, along Wedgemount Trail to Wedgemount Lake, 50°10.1'N, 122°50.2'W, elev. 1450 m, corticolous on horizontal trunks of Alnus alnobetula subsp. sinuata over creek in old-growth coniferous forest, 25 Sept 2000, T. Tønsberg 28708 (BG, CANL, UBC). - U.S.A. Alaska: City and Borough of Juneau, along trail from Juneau to Mt. Robert, 58°17.8'N, 134°22.8'W, elev. 620-630 m, corticolous on ± horizontal trunks of Alnus alnobetula subsp. sinuata, 7 Sept 1999, T. Tønsberg 27490 (BG); 58°17.7'N, 134°22.8'W, elev. 700 m, corticolous on ± horizontal trunks of Alnus alnobetula subsp. sinuata, 7 Sept 1999, T. Tønsberg 27495 (BG); 58°17.7'N, 134°22.5'W, elev. 740-750 m, corticolous on ± horizontal, dead trunks of Alnus alnobetula subsp. sinuata, 7 Sept 1999, T. Tønsberg 27497, 27499, 27500 (BG); 58 °17.6'N, 134°22.2'W, elev. 800-850 m, corticolous on ± horizontal trunks of Alnus alnobetula subsp. sinuata, 7 Sept 1999, T. Tønsberg 27501 (BG). Washington: Cowlitz Co., 7-8 km SW of summit of Mt St. Helens, E of Goat Mtn, NE of Goat Marsh Lake, N of Coldspring Creek, W of gravel Rd FR 8123, 46°10'N, 122°17'W, elev. 900-1000 m, corticolous on Alnus alnobetula subsp. sinuata, 23 June 1995, T. Tønsberg 23432 (BG); corticolous on the underside of slightly leaning trunk of Alnus rubra in woodland with mature Alnus rubra and some large Populus , 23 June 1995, T. Tønsberg 23440 (BG); 8 Aug 1996, T. Tønsberg 24114 (BG); corticolous on Alnus alnobetula subsp. sinuata in swamp, 8 Aug 1996, T. Tønsberg 24125 (BG); Lewis Co., Mount Rainier National Park, Nisqually River gorge, along Hwy 706, just E of the bridge, 46°46.9'N, 121°45.7'W, elev. 1165 m, corticolous on horizontal trunks of Alnus alnobetula subsp. sinuata in NW-facing slope in river valley, 28 Sept 2000, T. Tønsberg 28771a (BG); 7 Oct 2018, T. Tønsberg 48200 & S. Bainbridge (BG, MORA, UPS, WTU); on branches of Alnus alnobetula subsp. sinuata, 7 Oct 2018, T. Tønsberg 48201 & S. Bainbridge (BG, MORA, WTU); T. Tønsberg 48202 & S. Bainbridge (BG).