Bulbothrix continua (Lynge) Hale. Phytologia 28(5): 480. 1974.

Benatti, Michel N., 2012, A review of the genus Bulbothrix Hale: the species with medullary salazinic acid lacking vegetative propagules, MycoKeys 5, pp. 1-30 : 5-6

Bulbothrix continua (Lynge) Hale. Phytologia 28(5): 480. 1974. Figures 1-2

Parmelia continua Lynge. Arkiv för Botanik 13(13): 109. 1914. [Basionym]

Holotype.

Brasiliae civit Matto Grosso, Serra da Chapada, Buriti, leg. Malme s.n., 19-VI-1894 (S!).

Description.

Thallus subirregularly laciniate, grayish green in the herbarium, up to 3.8 cm diam., subcoriaceous, corticolous; upper cortex 15.0−22.5 µm thick, algal layer 25.0−37.5 µm thick, medulla 67.5−85.0 µm thick, lower cortex 20.0−25.0 µm thick. Laciniae anisotomically to irregularly dichotomously branched, 0.8-1.9 (-2.3) mm wide, slightly imbricate, rarely becoming crowded at the center, adnate and adpressed, with flat, subtruncate apices; margins plane, smooth and sinuous to crenate, entire, occasionally sublacinulate; axils oval. Upper surface smooth and continuous, becoming rugose and irregularly cracked in some parts; laminal ciliary bulbs absent. Adventitious marginal lacinulae scarce and restrict to older parts, short, 0.2-0.5 × 0.1-0.5 mm, plane, simple to rarely furcate; apices truncate; lower side concolorous to the lower marginal zone. Maculae absent. Cilia black, without or with simple apices, commonly bent downwards, 0.05-0.40 × ca. 0.03 mm, with semi-immerse to emerse bulbate bases 0.05-0.15 (-0.25) mm wide, abundant throughout the margin spaced 0.05−0.10 mm from each other to contiguous, solitary or in small groups at the crenae and axils, scarce at the apices of the laciniae. Soredia, Pustulae and Isidia absent. Medulla white. Lower surface brown to pale brown, shiny to opaque, smooth to subrugose, weakly papillate, moderately rhizinate. Marginal zone brown to pale brown, indistinct from the center, shiny to opaque, smooth, weakly papillate, weakly to densely rhizinate. Rhizinae black to pale brown brown, partially white or with whitish apices when close to the margins, simple or sometimes irregularly branched, commonly with bulbate bases, 0.10-0.65 × 0.03-0.10 mm, frequent but becoming abundant close to the margins or scarce at some other parts, sometimes agglutinated, evenly distributed. Apothecia concave to plane or convex, adnate to sessile and distended over the laciniae, 0.4-3.7 mm diam., laminal; margin smooth to subcrenate, ecoronate; amphithecium smooth, without ornamentations. Disc pale brown, epruinose, imperforate; epithecium 15.0-20.0 mm high; hymenium 50.0−62.5 µm high; subhymenium 15.0−22.5 µm high. Ascospores ellipsoid to oval, 9.0-13.5 × 5.0-7.5 µm; epispore ca. 1.0 mm. Pycnidia common, laminal, immersed, with black ostioles. Conidia baciliform 5.0−7.5 × 1.0 µm.

TLC/HPLC: cortical atranorin, medullary salazinic and consalazinic acids (see also Hale 1976).

Distribution.

South America: Brazil: State of Mato Grosso ( Lynge 1914). Here is reported new for the Brazilian State of São Paulo.

Additional specimens examined.

Brazil, Mato Grosso State, Santa Anna da Chapada, Buriti Municipality, leg. G. O. Malme s.n., 19-IV-1894 (US). Idem, São Paulo State, 6 km SW of Jaboticabal, 21°35'S, 48°35'W, on trees in “cerradão” (savannah), leg. A. Fletcher 10108, 1-V-1975 (BM). Idem, São Manuel Municipality, Fazenda Palmeira da Serra, unofficial private cerrado (savannah) reserve, on tree trunk in the cerrado, leg. M. P. Marcelli & S. B. Barbosa 35232, 03-VI-2003 (SP, paratype of Bulbothrix vainioi ). Idem, Santa Rita do Passa Quatro Municipality, Fazenda Vassununga, km 259 of Anhanguera Highway, 760 m, transition from cerrado to “cerradão” (savannah), trees with signs of old burns, on a tree thin twig, leg. M. P. Marcelli & S. B. L. Morretes 16055, 21-IX-1978 (SP). Idem, Moji-Guaçu Municipality, Fazenda Campininha, Estação Biológica de Moji-Guaçu, illuminated, dry savannah, on tree thin twig, leg. M. P. Marcelli 15885, 29-VI-1979 (SP).

Comments.

The holotype (Figs 1-2) consists of a small, entire thallus, in good condition. The material contains several apothecia at different stages of maturity with well developed ascospores, and some pycnidia. It is on a small piece of tree bark but with the laciniae apices free from the substrate, and is not glued to cardboard. There is no trace of true maculae in the upper cortex or in the amphithecia, although the cortex is in fact somewhat pale and shiny.

Hale (1960) mentioned that ' Parmelia ' continua was an unusual member of the section Hypotrachyna Vainio, without soredia or isidia and producing salazinic acid, believing at first that it might be a non-isidiate variety of ' Parmelia ' cinerascens Lynge. Latter, Hale and Kurokawa (1964) included ' Parmelia ' continua in the key for the ' Parmelia 'species that composed the Subsection Bicornutae Series Bicornutae , separating ' Parmelia ' continua from ' Parmelia ' hypocraea Vainio by the absence vs. presence of cortical maculae, respectively.

Shortly after the recombination of ' Parmelia ' continua into Bulbothrix ( Hale 1974), Hale (1976a) placed Bulbothrix continua in the synonymy of Bulbothrix hypocraea (Vainio) Hale, without any explanation. Most probably, Hale decided to synonymize them because of their great morphological similarity. However, I am inclined to accept Hale´s first interpretation (1974), since the presence of maculae implies a fundamentally different anatomic conformation of the medullary hyphae, as observed by Barbosa and Marcelli (2010, 2011) in the genus Parmotrema .

Compared with the specimens of Bulbothrix continua , those of Bulbothrix hypocraea are always quite maculate, and their thalli often form wider laciniae than those of Bulbothrix continua . Hale (1976a) mentioned that the discs of the apothecia in Bulbothrix hypocraea have a burnt amber color. However, Marcelli (1993) cited a disc color, shape and distribution of cilia different than those described by Hale, more similar to Bulbothrix continua .

Bulbothrix linteolocarpa Marcelli differs by the much narrower laciniae, barely exceeding 0.5 mm, that are also more linear with contiguous cilia forming long apices. As they mature, apothecia of Bulbothrix linteolocarpa continually adapt to the conformation of the surface, settling on the laciniae as if they were spreading over them. Two specimens of uncertain identity cited by Marcelli (1993) among the examined material of Bulbothrix linteolocarpa were actually found to be of Bulbothrix continua .

Bulbothrix sensibilis (Steiner & Zahlbruckner) Hale differs from Bulbothrix continua equally by the presence of cortical maculae and moreover by the shiny black lower cortex with dark brown margins. Bulbothrix setschwanensis (Zahlbruckner) Hale differs by the larger laciniae (ca. 1.5−5.0 mm wide) and by the size of the ascospores (usually 12.0−19.0 × 7.0−10.0 µm).