Bulbothrix hypocraea (Vain.) 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 : 9-12

Bulbothrix hypocraea (Vain.) Hale. Phytologia 28(5): 480. 1974. Figures 4-9

Parmelia hypocraea Vainio. Catalogue of the African Plants Collected by F. Welwitsch2(2): 400. 1901. [Basionym]

? Parmelia leptascea Stein. & Zahlb. Botanische Jahrbücher für Systematik 60: 514. 1926. [Synonyms]

Parmelia proboscidea var. saxicola CengiaSambo. Nuovo Giornale Botanico Italiano 45: 380. 1938.

Lectotype.

Angola, Huilla (3800 ad 5500 ped. s. m.), ad corticem arborum Leguminosarum in sylvis densis juxta flumen Monino, ca. 14°16°S, leg. Welwitsch 32 pro parte, IV-1860 (TUR-V!, duplicate at BM!).

Description.

Thallus sublinearly to subirregularly laciniate to sublaciniate, light dusky gray in the herbarium, in fragments up to 5.2 cm diam., coriaceous to subcoriaceous, corticolous or rarely saxicolous; upper cortex 15.0−25.0 µm thick, algal layer 25.0−42.5 µm thick, medulla 75.0−125.0 µm thick, lower cortex 12.5−20.0 µm thick. Laciniae anisotomicaly dichotomously to irregularly branched, (0.5−) 0.9-2.6 (−3.0) mm wide, contiguous to slightly imbricate, rarely crowded at the center, ± adnate and loosely adpressed, with plane to slightly involute or revolute, truncate, subtruncate or subrounded apices; margins plane to subplane, smooth to sinuous and subcrenate or subirregular, entire to slightly incised, not lacinulate; axils oval to irregular. Upper cortex mostly continuous, occasionally with some irregular cracks on older parts, smooth to subrugose; laminal ciliary bulbs absent. Adventitious marginal lacinulae absent, even on old parts. Maculae usually distinct, puntiform to efigurate, laminal on the thallus or on the amphithecia of the apothecia. Cilia black or rarely brown, without or with simple apices, often bent downwards, 0.05-0.65 × 0.03-0.05 mm, with semi-immerse to emerse, bulbate bases (0.05-) 0.10-0.30 mm wide (these partially enlarged or occasionally absent), frequent throughout the margins, solitary or in small groups in the crenae and axils spaced 0.05−0.20 mm from each other to occasionally contiguous, becoming absent or scarce at the apices of the laciniae and adjacent parts, usually absent or scarce in the apices of the laciniae and adjacent parts. Soredia, Isidia and Pustulae absent. Medulla white. Lower surface pale brown to ivory, opaque to slightly shiny, smooth, moderately rhizinate, sometimes up to the margins. Marginal zone indistinctly delimited from the center to slightly attenuate, 0.5-2.0 mm wide, pale brown to ivory, opaque to slightly shiny, smooth, weakly papillate, often rhizinate. Rhizinae ivory or light to dark brown, occasionally blackish, whitish or with white apices, simple or sometimes irregularly branched, partially with blackish bulbate bases or displaced bulbs, 0.10-0.80 (-1.10) × 0.05-0.10 mm, frequent, sometimes agglutinated, evenly distributed. Apothecia subconcave to subplane, becoming folded when old, sessile to adnate to substipiate, 0.3-8.2 mm diam., laminal to submarginal, ecoronate; margin subcrenate; amphithecia smooth occasionally fissured, without ornamentations. Disc pale brown to reddish brown, epruinose, imperforate; epithecium 7.5-17.5 µm high; hymenium 32.5−70.0 µm high; subhymenium 10.0−37.5 µm high. Ascospores ellipsoid to oval or subrounded, 7.0-14.0 × (5.0-) 6.0-8.0 mm; epispore ca. 1.0 mm. Pycnidia laminal, frequent mainly at the distal parts of the laciniae, immersed, with black ostioles. Conidia baciliform to weakly bifusiform (4.0−) 5.0−9.0 × 0.75 µm.

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

Distribution.

Africa ( Zahlbruckner 1926): Angola ( Vainio 1901, Hale 1976a), South Africa ( Hale 1976a), Kenya, Tanzania ( Sambo 1938, Swinscow and Krog 1988), Uganda ( Hale 1976a, Swinscow and Krog 1988), Rwanda ( Killmann and Fischer 2005, Bock et al. 2007), Rhodesia (nowadays Zimbabwe), Zaire, and Zambia ( Hale 1976a). South America: Venezuela ( López-Figueiras 1986, Marcano et al. 1996,) Brazil - States of Minas Gerais, Mato Grosso ( Hale 1976a), Paraná ( Eliasaro and Adler 1997, Eliasaro 2001), São Paulo ( Hale 1976a, Marcelli 1993) and Tocantins ( Eliasaro and Adler 1997).

Additional specimens examined.

Africa, Bakoba am Victoriasee, auf Baumrinden, Schröder 319 (W!, holotype of Parmelia leptascea ). Rhodesia (Zimbabwe), District Salisbury, Chindamora Reserve, Ngomakukira, epiphyte on Julbernardia globiflora , Swatzia madagascariensis etc., leg. H. Wild 5806, 10-VI-1962 (NY). Kenia, K4, Nth. Nyeri (1°30'S, 37°30'E), Lew Downs Ranch, 0 km W of Isiolo, Acacia woodland, leg. H. Ballev 660c, 4-XII-1981 (NY). Tanzania, Mahulo, Kipengere, loc. c. s. on rock, with Usnea densirostra , very mixed, leg. Eusébio 13 bis, 02-III-1935 (FI!, lectotype of Parmelia proboscidea var. saxicola, designate here as “B”). Brazil, Mato Grosso State, Serra do Roncador, riverine forest, 46 km north of Chavantina, Rio Vau, epiphyte, abundant, leg. G. T. Prance & N. T. Silva 59380A, 11-X-1964 (NY). Idem, Minas Gerais State, Lagoa Santa, leg. Warming s.n (M). Idem, São Paulo State, Brotas Municipality, NW side of intersectionof road to Campo Alegre with the Brotas-Itirapina road, arboreal semi-closed cerrado woodland, 22°17'S, 47°56'W, 750 m, leg. G. Eiten et al. 2976c, 16-VI-1961 (US). Idem, Santa Rita do Passa Quatro Municipality, fazenda Vassununga, km 259 of Anhanguera highway, on woody stem of vine, leg. M. P. Marcelli & B. L. Morretes 15628, 03-VI-1978 (SP). Idem, São Manuel Municipality, Fazenda Palmeira da Serra, non official particular cerrado (savannah) reserve, on tree trunk at the woods, leg. M. P. Marcelli & S. B. Barbosa 35680, 03-VI-2003 (SP).

Comments.

The lectotype (Figs 4-5) consists of three small fragments on bark glued to cardboard, and some smaller fragments packed in paper, free of substrate. The duplicate (Fig. 7) consists of three fragments, all on bark, one of them glued to cardboard (fragments free from substrate were used to see the features of the lower cortex). The type material has several pycnidia, restricted to the distal parts of the laciniae.

Bulbothrix hypocraea has the most strongly maculate thalli of the genus (Fig. 6). However, in very old herbalium material, such as the type, the maculae may become difficult to be see due to the darkening of the upper cortex and the staining of the medulla by the oxidized salazinic acid. In this case, a bright illumination and wetting the thalli make the maculae more visible.

Most cilia have an evident bulbate base, their apices are usually bent downwards and sometimes barely visible from above. Some cilia, however, have no basal bulb, but just a thickened, tapering base (possibly an early stage in the development of the cavity).

The color of the lower cortex varies from brown to ivory or cream, the marginal zone being slightly darker than the center (Fig. 5). The ivory color is the least common, and is similar to that observed in the lower margin of other Parmeliaceae (like Parmotrema species) which are white ivory when fresh, eventually changing color after time in the herbarium.

The swellings seen in the rhizines along its length are not actually endociliary pycnidia, as first suspected by Marcelli (1993), but basal or displaced bulbs. No conidia were found inside, but instead an oily substance like the one found in the marginal cilia. These structures have been noted already by Jungbluth (2006), who also called them bulbs. The color of the rhizines is somewhat variable, as in some thalli darker rhizines are commoner while in others these are of lighter tones. The bulbs are more difficult to see in blackish rhizines, since in this species they are usually thick.

Vainio (1901) mentioned a whitish color for the upper cortex (which suggests that the maculae of the type material were much more evident when the specimen was collected). He described the laciniae with a larger width (1.5-5.0 mm wide) than seen here. Hale (1976a) described Bulbothrix hypocraea with a more similar laciniae shape, branching pattern and width (1-3.5 mm) like was seen here.

The ascospore measurements provided by Hale (1976a), Swinscow and Krog (1988), Marcelli (1993), Eliasaro (2001), and Jungbluth (2006) do not vary significantly and are in agreement with those of Vainio (1901) and those obtained here.

The description by Eliasaro (2001) has narrower laciniae compared to others (0.5-1.0 mm wide), but agrees in all other characteristics. Eliasaro reports occasional small amounts of norstictic acid in her specimens. This is probably contamination, since it was not reported by other authors and not found in the specimens studied.

Swinscow and Krog (1988) described African material of Bulbothrix hypocraea that deviated by being emaculate or weakly maculate, with cilia often seen only as "black nodes" in the margins and with ascospores 8.0-10.0 × 3.0-5.0 mm, including some saxicolous specimens. From their perspective, it is close to the type of Parmelia leptascea Zahlbruckner and Steiner (W!). Unfortunately, this material was not sent on loan from O for comparison, although requested several times. The authors present an illustration showing small cilia composed solely of the bulbs. Jungbluth (2006) supposed that these specimens might belong to a different taxon, for which the name Parmelia leptascea might be available as seen here. Indeed no marginal cilia in the Parmelia leptascea holotype (Fig. 8) have apices, even the most developed, usually restricted only to bulbs. These are also more abundant than those seen in typical specimens of Bulbothrix hypocraea . However, besides the saxicolous habit, the laciniae usually crowded and with a larger maximum width, and the cilia aspect, no other significant differences were found with Bulbothrix hypocraea , althought the maculae are evident despite the dark tone acquired in herbarium. The variations found may be merely due to the substrate. More material is needed for a decision about the status of this material and a proposition of a new combination regarding Parmelia leptacea .

The type collection of Parmelia proboscidea var. saxicola Cengia Sambo (FI!) consists of a ciliate Parmotrema specimen with submarginal, pustular soralia, and two fragments of Bulbothrix hypocraea (Fig. 9, marked B) that make up the majority of the collection. Therefore the latter are appointed here as the lectotype, as it is in accordance to the species protologue. The comments of Cengia Sambo (1938) suggest that she did not realize that the parts were from two different species. The author did not describe the material in detail, only commenting that the laciniae were variable, the smaller thalli being so because of being saxicolous.

Bulbothrix setschwanensis (Zahlbruckner) Hale differs by the absence of cortical maculae and by larger ascospores 12.0−19.0 × 6.0−9.0 µm. Hale (1976a) distinguished this species from Bulbothrix hypocraea in his key also by the width of the laciniae, but although there is a tendency for specimens of Bulbothrix setschwanensis to have wider laciniae, there are specimens with laciniae the same width typically found in specimens of Bulbothrix hypocraea , such as the holotype. Basically, the largest laciniae of Bulbothrix hypocraea are of about the same width as the smallest of Bulbothrix setchwanensis . The absence of maculae and the spore size are reliable characters to differentiate between the two species.

Bulbothrix linteolocarpa Marcelli was compared to Bulbothrix hypocraea by Jungbluth (2006). It differs clearly by the much narrower linear laciniae 0.2−0.5 (−0.8) mm wide, by the emaculate upper cortex, and by the cilia with smaller bulbate bases and longer apices. The apothecia are also different in shape, being flatter and usually stretched over the laciniae.

Among other similar species, Bulbothrix sensibilis (Steiner & Zahlbruckner) Hale was compared to Bulbothrix hypocraea by Hale (1976a) and Jungbluth (2006), and it differs by the black lower cortex with brown margins and by the weaker maculae of the upper cortex. Bulbothrix subcoronata ( Müller Argoviensis) Hale (G!) was compared to Bulbothrix hypocraea by Eliasaro (2001). The type material differs by a black lower cortex with brown margins, coronate apothecia containing smaller ascospores (5.0-7.5 × 4.0−5.5 mm) and medullary norstictic acid. Bulbothrix meizospora (Nylander) Hale was compared by Jungbluth (2006), and differs by the weaker maculae of the upper cortex, a black lower cortex with brown or black margins, and by the larger ascospores (12.0−22.0 × 9.0−14.0 µm).