Bacidina Vězda
Type : B. phacodes (Körb.) Vězda [=Bacidia phacodes Körb.]
Description : Thallus crustose, continuous, without cracks or rimose to areolate to granular, smooth to wrinkled or verrucose or subsquamulose, sometimes discontinous of discrete to contiguous areolae; prothallus absent; without soredia or isidia. Goniocysts common, sometimes covering most of thallus, usually ±pale-green. Upper cortex (not present in goniocysts) of one inner layer of anticlinal or irregular hyphae, and an outer epinecral layer. Photobiont layer continuous or discontinuous. Photobiont chlorococcoid. Medulla and lower cortex absent. Ascomata apothecia, ±sessile, biatorine, rarely with an additional thin, thalline margin, weakly pigmented, pale-pink or yellow to pale-orange. Disc plane soon becoming ±convex. Proper exciple without oil droplets or crystals. Hypothecium colourless, or sometime yellowish to brown, without crystals or oil droplets, not chondroid. Hymenium 40–80 μm tall, I+ blue, colourless below, pigmented in a diffuse layer above. Hamathecium of paraphyses, unbranched or ±branched in upper parts, sparingly anastomosing; apices not at all swollen to ±clavate. Asci clavate, Lecanora -type, surrounded by a thin, amyloid gelatinous sheet, tholus amyloid, with a high or low, blunt axial body; ocular chamber present or absent, low or high, blunt or pointed. Ascospores 8 per ascus, acicular to subbacillar, 1–12-septate, straight, curved or sigmoid. straight or coiled in ascus, colourless, rather thick-walled, without perispore or ornamentation, 16–90 μm long, 0.9–3.3 μm wide, easily separating at maturity. Conidiomata pycnidia, immersed, concolorous with, or paler than, apothecia. Conidia of five different types (Ekman 1996a: 113). No demonstrable chemistry.
Bacidina was segregated from Bacidia because of the different ascus structure and the thallus that is finely granular composed of goniocysts (Vězda 1991; Sérusiaux 1993: 453). It is included in the family Ramalinaceae (Ekman 2001, 2004b; Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005. At present c. 30 species are recognised (Ekman 2004b). Taxonomy and systematics of the genus is discussed by Ekman (1996a, 1996b, 2004b), and species occurring in Spain and Portugal are discussed by Llop & Hladun (2000). It is conserved against the competing names Lichingoldia D.Hawksw. & Poelt, Woessia D.Hawksw. & Poelt ms 2001: 269), though an older name, Lopacidia Kalb. (Kalb et al. 2000: 282), exists for this group of species. Sérusiaux et al. (2003: 5) recommend that no additional nomenclatural changes should be proposed as long as the monophyly of the entire group has not been definitely proved.
Ekman (2001: 36–37) characterises Bacidina as follows: (1) Lichenised with green, chlorococcoid algae. (2) Thallus crustose, often partly or entirely dissolving into goniocysts. Upper cortex of two layers, the outer, an epinecral layer without crystals. (3) Biatorine, lecideine or rarely zeorine apothecia. (4) Proper exciple well-developed, hyphae indistinctly or distinctly radiating, commonly richly furcate, but sparingly or not anastomosing. (5) Hypothecium not chondroid, distinctly delimited from, and different in texture to, proper exciple. (6) Paraphyses unbranched or branched in upper parts, without a thick gelatinous wall in upperparts. (7) Hymenium and subhymenium I+ blue, sometimes pigmented in upper parts. (8) Apical tholus of ascus I+ blue, with a narrow or wide c-layer, with a high or low, blunt axial body, sometimes penetrating through entire d-layer, the width of which is more than one-third of the d-layer; ocular chamber absent or present, low or high, blunt or pointed (Malcolm & Galloway 1997: 186). (9) Ascospores acicular, at maturity with 3 or more transverse septa; colourless, thick-walled, without a perispore or ornamentation. (10) No detectable secondary chemistry. Two species are recorded from New Zealand.
