Bulbothrix lordhowensis Elix. Mycotaxon 56(1): 231. 1995.

Benatti, Michel N., 2012, A review of the genus Bulbothrix Hale: the species with medullary norstictic or protocetraric acids, MycoKeys 2, pp. 1-28 : 7-9

Bulbothrix lordhowensis Elix. Mycotaxon 56(1): 231. 1995. Figure 8

Holotype.

Australia, New South Wales, Lord Howe Island, along track to Mutton Bird Point, 31°32'45"S, 159°05'00"E, 60 m alt., dry lowland forest with basalt outcrops, on dead canopy branches, leg. J. A. Elix 32781, 21-VI-1992 (CANB!, isotypes HO and MEL).

Description.

Thallus sublinearly to linearly laciniate, turning pale dusky green in the herbarium, fragments up to 2.2 cm diam., subcoriaceous, corticicolous; upper cortex 12.5−20.0 µm thick, algal layer 15.0−22.5 µm thick, medulla 57.5−70.0 µm thick, lower cortex 15.0−22.5 µm thick. Laciniae dichotomously or trichotomously branched or occasionally slightly irregularly ramified, 0.3-0.6 mm wide, contiguous to occasionally imbricate or rarely crowded, adnate and appressed, with flat to slightly involute, subtruncate to truncate apices, the margins flat to subconvex, crenate to subirregular, entire to slightly incised and occasionally sublacinulate, the axils oval or irregularly shaped, upper cortex continuous and smooth, frequently with irregular cracks mainly on older parts, laminal ciliary bulbs common and frequent. Lacinulae scarce, marginal and adventitious, short, flat, 0.10-0.60 × 0.05-0.20 mm, simple or irregularly branched, truncate or sometimes acute, underside concolorous with the lower marginal zone. Maculae absent (not to be confused with marks left by detachment of the isidia, sometimes deep, exposing the medulla). Cilia black or occasionally brown, with simple to furcate or trifurcate apices, sometimes subdichotomously branched in the axils, 0.05-0.25 (−0.40) × ca. 0.03 mm, with semi-immerse to emerse bulbate bases ca. 0.05 (-0.10) mm wide, contiguous along the margins or up to 0.5 mm spaced from each other, usually absent or scarce on the apices of the laciniae. Soredia and pustulae absent. Isidia frequent, laminal, granular to short smooth cylindrical, straight, 0.05-0.10 (−0.20) × ca. 0.05 mm, simple to sometimes sparsely branched, erect, firm to caducous, darkened and with dark brown apices, eciliate. Medulla white. Lower surface black, shiny, smooth to subrugose, densely rhizinate with some open parts. Marginal zone attenuate, brown, shiny, 0.3-0.5 mm wide, smooth, generally rhizinate. Rhizinae black, sometimes with brown apices, initially simple becoming furcate and then dichotomous, apparently without bulbs, 0.10-0.40 × ca. 0.03-0.05 mm, abundant, evenly distributed. Apothecia and pycnidia not found.

Spot tests.

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

TLC/HPLC.

cortical atranorin and chloroatranorin, medullary norstictic acid and two unknown substances ( Elix 1995).

Distribution

. Oceania. Australia ( Elix 1995).

Comments.

The holotype (Fig. 8) consists of six small fragments in good condition, along with a small and fragile fragment. Isidia are or were present on all specimens; the latter can be identified by the marks that are left where the isidia broke off. A fragment is covering a Sarcographa specimen, while another fragment is partially covered by a small, sorediate Physcia specimen.

There are frequent laminal ciliary bulbs in the holotype. Part of the observed laminal bulbs were first interpreted as poorly developed pycnidia or even parasitic fungi, which has been proven wrong. Besides being generally small in size also in the margins, some of the laminal bulbs are poorly developed.

This is one of the species with the narrowest laciniae in the genus, barely exceeding 0.5 mm in width. The cilia are evidently bulbate, with very small bulbs. Bulbs were not seen in the rhizinae, and if they occur, they should be rare and very subtle. The isidia are very small and appear as unornamented, darkened grains. When detached, they can leave strong marks, resembling spilled medulla that comes out through the cortex. They are easily distinguishable from maculae.

Bulbothrix queenslandica (Elix & Stevens) Elix (MEL!, US!), differs by the larger laciniae (0.5−1.5 mm wide), cortical maculae, concolorous and ciliate isidia, and the absence of medullary substances. Bulbothrix pigmentacea (Hale) Hale probably has only small amounts of gyrophoric acid, and random spots of a K− reddish pigment in the medulla, rhizinae and lower cortex. For comparison of Bulbothrix lordhowensis with Bulbothrix queenslandica and Bulbothrix pigmentacea (Hale) Hale, see also Elix (1995).

Among the isidiate species with medullary norstictic acid, Bulbothrix ventricosa (Hale & Kurokawa) Hale differs by the larger laciniae (1.0-5.0 mm wide) with rounded apices, less frequent cilia and rhizinae with simple apices, larger and simple, concolorous isidia (which leave no such conspicuous marks as in Bulbothrix lordhowensis ), and by the frequently mottled coloration of the lower cortex. Bulbothrix cinerea Marcelli & Kalb differs from Bulbothrix lordhowensis by being saxicolous, having larger laciniae (0.5−2.5 mm wide), and lacking laminal ciliary bulbs. It has cilia and rhizinae with simple apices and a pale brown lower cortex.

Bulbothrix subtabacina (Elix) Elix (MEL!, CANB!) has larger laciniae (0.5-1.0 mm wide), a maculate and very brittle upper cortex, concolorous isidia, and medullary salazinic acid. Bulbothrix tabacina (Montagne & Bosch) Hale (L!, PC!) has even larger (1.0-5.0 mm wide), irregularly branched laciniae with more rounded apices, cilia and rhizinae with simple apices, and also contains medullary salazinic acid.