Bulbothrix setschwanensis (Zahlb.) Hale. Phytologia 28: 481. 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 : 19-21

Bulbothrix setschwanensis (Zahlb.) Hale. Phytologia 28: 481. 1974. Figure 16

Parmelia setschwanensis Zahlb. Symbolae Sinicae 3: 184. 1930. [Basionym]

Holotype.

China, Prov. Setschwan austro-occid., in regionis siccae subtropicae convallis fluminis Yalung ad septentriones oppidi Yneyünen infra castelum Kwapi ram Pistacia weinmannifolia supra vic. Otang, alt. 2400-2500 m., leg. Handel-Mazzetti 2739, 30-V-1914 (WU!).

Description.

Thallus subirregularly to sublinearly laciniate, greenish gray in the herbarium, up to 7.0 cm diam., subcoriaceous, corticolous or ramulicolous; upper cortex 15.0−20.0 µm thick, algal layer 30.0−47.5 µm thick, medulla 87.5−110.0 µm thick, lower cortex 12.5−20.0 µm thick. Laciniae irregularly to partially to anisotomically dichotomously branched, contiguous to imbricate, 1.1-3.5 (-5.0) mm wide, adnate and adpressed, with ± flat, subrounded to subtruncate apices; margins flat, smooth and sinuous to crenate or or irregular, entire to slightly incised, occasionally sublacinulate; axils oval or irregular. Upper cortex mostly smooth and continuous, occasionally becoming subrugose and irregularly cracked; laminal ciliary bulbs absent. Adventitious marginal lacinulae scarce on older parts, short, 0.2-1.0 × 0.1-0.6 mm, plane, simple to irregularly branched; apices truncate or acute; lower side concolor with the lower marginal zone. Maculae absent. Cilia black, without or with simple apices, 0.05-0.30 (-0.50) × ca. 0.03 mm, with semi-immersed to emerse bulbate bases 0.05-0.25 mm wide, frequent to abundant along the margins, spaced 0.05−0.15 mm from each other to rarely contiguous, solitary or in small groups at the crenae and axils becoming scarce at the apices of the laciniae. Soredia, Isidia and Pustulae absent. Medulla white. Lower surface pale brown, opaque, smooth to subrugose, moderately rhizinate. Marginal zone pale brown, indistinctly delimited from the center, opaque, smooth to subrugose, weakly papillate, variably rhizinate. Rhizines brown or cream colored, simple, rarely with subtle displaced blackish bulbs, 0.05-0.80 × 0.03-0.05 mm, frequent becoming abundant near the margins, evenly distributed. Apothecia subconcave to plane, adnate to subpedicelate, 0.4−4.1 mm diam., laminal to submarginal, ecoronate; margin smooth to subcrenate or fissured; amphitecia smooth, without ornamentations. Disc light to dark brown, epruinose, imperforate; epithecium 7.5-12.5 mm high; hymenium 35.0−42.5 µm high; subhymenium 12.5−20.0 µm high. Ascospores ellipsoid to oval, (10.0−) 12.0−19.0 × 6.0−9.0 (−10.0) µm; epispore ca. 1.0 µm. Pycnidia laminal, frequent, immerse, with black ostioles. Conidia baciliform to weakly bifusiform (4.0−) 5.0−8.5 × ca. 0.75 µm.

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

Distribution.

Asia: China ( Zahlbruckner 1930, Hale 1976a), India ( Hale 1976a, Divakar and Upreti 2005), Nepal ( Hale 1976a, Kurokawa 1993, Divakar and Upreti 2005) and Thailand ( Wolseley and Aguirre-Hudson 1997, Wolseley et al. 2002, Ramkhamhaeng University Herbarium 2006).

Additional specimens examined.

India, Oriental India, prov. Central, Chavradadar, Manra distr., 3500 ft., leg. J.Masten s.n., XII-1900 (NY). Idem, Kolhapur, Maharashtra, Panhala Forest, leg. P. G. Pahvardhan & R. A. V. Prabhu 74.1007, 13-X-1974 (US). Idem, Índia, E. Himalayas, Darjeeling, West Bengal, Manibhanjan, 7700 ft., leg. C. G. Dharne & K. N. R. Chaudhuri 82, VI-1966 (SP). Pakistan, Lower Topa, Murree hills, on bark of Pinus excelsa, leg. S. H. Iqbal 844(?), 11-VII-1967 (US).

Comments.

The holotype (Fig. 16) consists of a thallus on a tree twig, together with other bark fragments containing smaller pieces. It is in a reasonable state of preservation, with some lobes and apothecia badly damaged. The material contains several apothecia at different stages of maturity with ascospores in good condition, and many pycnidia with conidia. There are some loose fragments, on which the lower cortex was observed.

Zahlbruckner (1930) described the species as not ciliate ("in marginibus non ciliatis"), since like Lynge (1914) thought that the bulbate cilia on the margins were rhizines. Zahlbruckner (1930) described the lower cortex as black with brown margins (subtus niger, excepta parte angusta marginali castaneo-fusca), but the analysis of the type material confirmed the statements of Hale (1976a) and Divakar and Upreti (2005) on the color to be pale brown (almost cream in some parts) from the center to the margins.

Zahlbruckner (1930) also mentioned ellipsoid to suboval ascospores 12.0-18.0 × 6.0-10.0 mm, but there is a note from Hale with the lectotype citing 12.0-15.0 × 7.0-8.0 mm, and the ascospores found measure (10.0-) 12.0-15.0 × 7.0-9.0 mm. The syntype was not located (W, according to Hale 1976a), and accordingly to his data probably should have ascospores 12.0−18.0 × 6.0−12.0 µm. Measurements made by Hale (1976a) and Divakar and Upreti (2005) respectively mention ascospores 12.0-19.0 × 6.0-9.0 and 10.0-19.0 × 6.0-9.0 µm encompassing the measurements mentioned above. The other specimens examined here have similar sized ascospores, generally above 12.0 × 7.0 µm. The occurrence of a similar ascospores size variety also occurs in Bulbothrix meizospora (Nylander) Hale.

Among similar species, Bulbothrix meizospora is morphologically close to Bulbothrix setschwanensis including the ascospores of similar size, but the has a distinct black lower cortex with brown margins, as cited by Hale (1976a) and Divakar and Upreti (2005).

Hale (1976a) compared Bulbothrix setschwanensis to Bulbothrix hypocraea (Vainio) Hale. This species differs by evident maculae in the upper cortex, the narrower laciniae width (ca. 0.5−2.5 mm wide) and by the smaller sizes of the ascospores (8.0−14.0 × 6.0−8.0 mm). Bulbothrix sensibilis (Steiner & Zahlbruckner) Hale and Bulbothrix meizospora cortices both differ from Bulbothrix setschwanensis by the black lower cortex with brown margins, presence of cortical maculae, and in the case of Bulbothrix sensibilis , also by the smaller ascospores 8.0−12.0 × 5.0−7.0 µm. Bulbothrix linteolocarpa Marcelli differs by the much narrower sublinear laciniae ca. 0.2−0.5 mm wide, and by the cilia with small bulbs and more evident apices that are more widespread along the margins rather than restricted to the crenae and axils of the laciniae.

Bulbothrix continua (Lynge) Hale differs by the narrower laciniae ca. 1.0−2.0 mm wide and by the smaller ascospores 9.0−13.5 × 5.0−7.5 µm. in direct comparison, morphologically its aspect more closely resembles that of Bulbothrix hypocraea , although the maculations are absent, while that of Bulbothrix setschwanensis is more akin to that of Bulbothrix meizospora . In a key in Hale and Kurokawa (1964) Bulbothrix continua was separated from Bulbothrix setschwanensis solely by the laciniae width and by the geographical distribution, the first thought to be endemic to South America and the other to Asia.

Originally described from China, the species is also known from India and Nepal ( Hale 1976a, Divakar and Upreti 2005), where it is endemic to the Himalayan mountain region. Bulbothrix setschwanensis has been used in in vitro experiments for the production of secondary metabolites and reduction of inhibitory activity or reduction of enzymes ( Behera and Makhija 2001, 2002, Behera et al. 2000).