Bulbothrix viatica Spielmann & Marcelli. Mycotaxon 103: 201. 2008.

Benatti, Michel N., 2012, A review of the genus Bulbothrix Hale: the species with medullary norstictic or protocetraric acids, MycoKeys 2, pp. 1-28 : 18-21

Bulbothrix viatica Spielmann & Marcelli. Mycotaxon 103: 201. 2008. Figures 16-17

Synonym.

Bulbothrix megapotamica Canêz & Marcelli. Mycotaxon 105: 225. 2008.

Holotype.

Brazil, Rio Grande do Sul State, Santa Cruz do Sul Municipality, margin of the highway RST-287, km 102, 29°41'03.3"S, 52°25'33.6"W, 150 m alt., roadside, on Eucalyptus branch, 28-VII- 2003, leg. A.A. Spielmann 389 (SP!).

Description.

Thallus sublinearly or subirregularly laciniate to sublaciniate, turning dusky green in the herbarium, fragments up to 5.3 cm diam., subcoriaceous to submembranaceous, corticicolous or ramulicolous; upper cortex 7.5−15.0 µm thick, algal layer 25.0−37.5 µm thick, medulla 37.5−72.5 µm thick, lower cortex 12.5−25.0 µm thick. Laciniae anisotomically dichotomously to irregularly branched, (0.4−) 1.1-4.7 mm wide, contiguous to sometimes slightly imbricate or rarely crowded in the center, adnate and loosely adpressed, with flat to slightly involute or revolute, subtruncate to subrotund apices, the margins flat to slightly involute, sinuous to crenate or subirregular, entire to slightly incised, rarely sublacinulate, axils oval to irregular, upper cortex continuous with irregular fissures in old parts, smooth to subrugose, laminal ciliary bulbs common, absent to abundant, usually frequent, mainly on young distal parts. Adventitious marginal lacinulae scarce on older parts, short, 0.2-1.2 × 0.1-0.4 mm, flat, simple to furcate or irregularly branched, apices subtruncate, lower side concolorous with the lower marginal zone. Maculae absent. Cilia black, with usually simple, sometimes double or absent, frequently downward-bent apices, 0.05-0.35 (−0.60) × ca. 0.03 mm, with emerse bulbate bases 0.05−0.15 (-0.35) mm wide, frequent along the margins in the crenulations and axils of the laciniae, spaced 0.05−0.10 mm from each other, occasionally becoming contiguous, solitary or in small groups, absent or scarce at the apices of the laciniae and in some parts of the margins. Soredia, pustulae and isidia absent. Medulla white. Lower surface brown to dark brown, sometimes blackened in some small parts [black, mottled with brown in variable intermediary levels to completely brown], opaque to shiny, smooth to rugose, moderately rhizinate except at the margins. Marginal zone brown to pale brown, black or variegate, attenuated or indistinct from the center, shiny, 0.5-4.0 mm wide, smooth to subrugose or subvenate, papillate, becoming rhizinate towards the center. Rhizinae black to dark or pale brown, occasionally with whitish apices, simple or rare irregularly branched, partially with bulbate bases, 0.10-0.50 (−0.80) × 0.03-0.05 mm, frequent but sometimes becoming more abundant at some spots, evenly distributed. Apothecia subconcave to concave or urceolate, occasionally subplane, adnate to substipitate, 0.5-5.4 mm diam., laminal, margins smooth to crenate, coronate (bulbs appearing in the crenulations), amphithecium smooth to rugose without ornamentations. Disc brown to pale brown, epruinose, imperforate, epithecium 7.5-12.5 µm high, hymenium 55.0−75.0 µm high, subhymenium 12.5−27.5 µm high. Ascospores ellipsoid to oval, (10.0−) 12.0−16.0 (−18.0) × (6.0−) 7.0−10.0 (−11.0) µm, epispore 1.0−1.5 µm. Pycnidia frequent, submarginal to laminal, immerse, with brown or black ostioles; conidia weakly to distinctly bifusiform (4.0−) 5.0−7.5 × 1.0 µm.

Spot tests.

upper cortex K+ yellow, UV-; medulla K+ yellow→orange or light red, C-, KC-, P+ orange, UV-.

TLC/HPLC.

cortical atranorin, medullary norstictic and connorstictic acids (see also Spielmann 2005, Spielmann and Marcelli 2008).

Distribution.

South America. Brazil: Rio Grande do Sul ( Canêz 2005, Spielmann 2005, Marcelli and Canêz 2008, Spielmann and Marcelli 2008) and São Paulo ( Jungbluth 2006). Here is cited for the Brazilian States of Goiás, Minas Gerais, and Rio de Janeiro.

Additional specimens examined.

Brazil, Goiás State, Serra Geral do Paranã, on bark of Kielmeyera , in cerrado, cerrado and campo on slopes, ca. 1 km S of São João Aliança, ca. 850 m, leg. Irwin et al. 31977a, 16-III-1971 (NY). Idem, ca. 10 km S of São João da Aliança, campo e cerrado, cerrado, on trunk of small tree ( Hymenaea sp.), 950 m, leg. H. S. Irwin, R. M. Harley & G. L. Smith 32074, 17-III-1971 (US). Idem, Minas Gerais State, Catas Altas Municipality, Serra do Caraça, Parque Natural do Caraça, , on tree trunk at the foot of the Morro do Calvário at the side of the hotel, leg. M.P. Marcelli & A.E. Luchi 29654, 10-XI-1995 (SP). Idem, Rio de Janeiro State, leg. A. Glaziou 1825 (UPS). Idem, São Paulo State, Santa Rita do Passa Quatro Municipality, Vassununga farm, Anhanguera Highway km 259, on thin small tree thin twig in the dense cerrado, leg. M.P. Marcelli & C.H. Ribeiro 17508, 15-VI-1979 (SP). Idem, Rio Grande do Sul State, Sinimbu Municipality, Cava Funda, 29°27'40"S, 52°31'09.5"W, corticicolous, in the embankment of the road in open place, leg. A.A. Spielmann & L.S. Canêz 1318, 05-I-2004 (SP). Idem, Herveiras Municipality, 29°27'12.5"S, 52°37'57.7"W, 540 m alt., in trunk of Eucalyptus sp., in the embankment of the road in open place, leg. A.A. Spielmann, L.S. Canêz & C. Trentin 714, 24-I-2004 (SP). Idem, Sobradinho Municipality, margin of RST-481 road, near the road clover, 29°24'20.2"S, 52°01'25.9"W, 375 m alt., corticicolous in bush in the embankment in open place, leg. A.A. Spielmann 341, 17-VII-2003 (SP). Idem, Vacaria Municipality, Fazenda da Estrela, 28°04'58.9"S, 50°56'48.9"W, 850 m alt., open field, on a shrub branch, 23-II-2003, leg. L.S. Canêz & A.A. Spielmann 146 (holotype of Bulbothrix megapotamica , SP!).

Comments.

The holotype (Fig. 16) is a small fragmented piece in excellent condition, free of substrate, with a predominantly brown lower surface. The upper surface contains many laminal bulbs and pycnidia, and several well-developed apothecia, containing mature ascospores.

Bulbothrix viatica is probably the parental non-isidiate morph of Bulbothrix ventricosa . Both are very similar in almost all characteristics (especially regarding the color variation of the lower cortex and the frequent presence of laminal ciliary bulbs), differing almost only by the presence of cortical maculae and isidia in Bulbothrix ventricosa .

The same color variations found in the lower cortex of specimens of Bulbothrix viatica were also found in specimens of Bulbothrix ventricosa (see there). The most common is different tinges of brown mixed with dark or blackish spots of variable sizes (as in the holotype), but some thalli, especially the smaller ones, tend to have a darker or black coloration.

The laminal ciliary bulbs were overlooked by Spielmann and Marcelli (2008). They are clearly present in part of the material cited by these authors, including the holotype. Admittedly, specimens without laminal bulbs do also occur and are more common in Bulbothrix viatica than in Bulbothrix ventricosa . The structure of the laminal bulbs is the same as in Bulbothrix ventricosa (see above). The eventual appearance of these bulbs in these species might be conditioned to thallus development and environmental stimuli.

As shown by Marcelli and Canêz (2008), there are at least three morphologically similar species, with norstictic acid and simple cilia with globose bulbate bases, common in the southern and southeastern regions of Brazil which formerly included in Bulbothrix subcoronata . They are differentiated by the size of the ascospores, the presence or absence of laminal ciliary bulbs and the coloration of the lower cortex. The ones currently known are Bulbothrix regneliana , Bulbothrix ventricosa and Bulbothrix viatica and possibly true Bulbothrix subcoronata . The specimens with a brown lower surface with ascospores 7−11 µm long reported by Hale (1976) as Bulbothrix subcoronata are possibly Bulbothrix regnelliana , while the specimens with ascospores (10−) 12−18 (−20) µm long and a black or brown lower surface cited in other works might be Bulbothrix viatica .

Accordingly to the literature, Bulbothrix subcoronata ( Müller Argoviensis) Hale is the species most easily confusable with Bulbothrix viatica ,but it has narrower and more sublinear laciniae (ca. 0.5−1.0 mm wide), no laminal ciliary bulbs, a black lower cortex with distinct brown margins, and retrorse rhizinae on the apothecia. The ascospores are smaller, more rounded (5.0−7.5 × 4.0−5.5 µm) than described by Müller Argoviensis (1887).

The holotype of Bulbothrix megapotamica Canêz & Marcelli has narrow and truncate laciniae (0.5−1.5 mm wide), lacks laminal ciliary bulbs (with many pycnidia), and a black lower surface with brown margins, and almost no formation of bulbs in the rhizinae (the few seen are subtle). However, there are specimens with intermediary characteristics who show that Bulbothrix megapotamica is a synonym of Bulbothrix viatica .

Bulbothrix hypocraea (Vainio) Hale differs from Bulbothrix viatica by the absence of ciliary bulbs on a maculate upper cortex, a predominantly ochraceously or creamy pale brown lower surface, creamy or pale brown rhizinae, ecoronate apothecia with ascospores 8.0−14.0 × 6.0−8.0 µm and the presence of medullary salazinic acid. The similar Bulbothrix continua (Lynge) Hale is also emaculate, but has narrower (ca. 1.0−2.0 mm wide) and dichotomous sublinear laciniae and contains salazinic acid in the medulla.

Bulbothrix linteolocarpa Marcelli differs by the very narrow, sublinear laciniae (ca. 0.3−0.5 mm wide), a pale brown lower cortex with darker margins, simple to furcate or irregularly branched rhizinae, ecoronate flat apothecia stretched over the laciniae, and salazinic acid in the medulla.

Bulbothrix setschwanensis (Zahlbruckner) Hale differs by having a pale brown lower surface with indistinct margins, rhizinae without basal bulbs, ecoronate apothecia containing ascospores 12.0−19.0 × 6.0−9.0 µm, and medullary salazinic acid.

Bulbothrix meizospora (Nylander) Hale differs by the larger laciniae (1.5−6.0 mm wide), a shiny black lower surface with distinct brown margins, ecoronate apothecia with larger ascospores (12.0−20.0 × 8.0−12.0 µm), and medullary salazinic acid. Bulbothrix sensibilis (Steiner & Zahlbruckner) Halediffers by almost the same characteristics, but has smaller ascospores, 7.0-11.0 × 5.0-7.0 mm.