Bulletin of the British Museum (Natural History)

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LICHEN GENUS MICAREA IN EUROPE 97 apices never regularly clavate or capitate and never with a dark brown apical 'cap', but sometimes irregularly incrassate and sometimes with thickened pigmented walls in about upper 5-15 ixm; in addition, some species have a few stout paraphyses (which are c. 2-3 /xm wide, and, in some cases, pigmented throughout their length) occurring as scattered individuals or small fascicles. Hypothecium (including subhymenium) variously pigmented, of interwoven hyphae that become outwardly orientated towards the hymenium, mixed with wider, short-celled ascogenous hyphae. Excipulum often absent or indistinct, if discernible then non-amyloid (or ± so) and composed of radiating branched and anastomosing paraphysis-like hyphae that become distinct and ± separate in K. Pycnidia often present, very varied in form from immersed to sessile or stalked, the stalks (pycnidiophores) sometimes branched. Pycnidial walls hyaline or pigmented. Conidiogenous cells ampulliform to cylindrical (sometimes with swollen base), phialidic, sometimes with 1-3 proliferations. Conidia hyaline, smooth-walled, of three basic types: (i) microconidia - ± cylindrical, aseptate, eguttulate, in range 3-5-9x0-5-l fxm, borne in immersed to sessile pycnidia usually
98 BRIAN JOHN COPPINS species in at least one case. Micarea intrusa {q.v.) possibly provides a link between the two genera, and its inclusion in Micarea, rather than Scoliciosporum, is mainly on the grounds of spore-type. The differences between the two genera are admittedly unclear and ill-defined at the present time, and will certainly require re-appraisal as our knowledge of morphological, ontogenetic, and phylogenetic aspects in the Lecideaceae increases. A genus which may be closely related to both Micarea and Scoliciosporum is Strangospora Massal.; it shares with them unsophisticated apothecial and thallus structures, and similar ecological requirements. However, Strangospora differs in having polysporous asci with aseptate, globose spores, although the asci do appear to be of the Lecanora-typQ. The monotypic genus Steinia Korber is represented by S. geophana (Nyl.) Stein, whose small, black, immargin- ate apothecia occurring on shaded substrate (soil, rotten wood, rocks, stones, etc.) are easily confused in the field with those of some Micarea species. However, it is easily distinguished in microscopical preparations by its 16-spored asci with globose spores, and simple, slender paraphyses. In addition, its asci are not of the Lecanora-typQ, although their apices are each provided with a broad, amyloid plug. Micarea appears to have some affinities to Psilolechia Massal., and the two genera are compared in the discussion of Psilolechia clavulifera (p. 376). Micarea may also be close to the predominantly foliicolous Byssoloma Trevisan, but species of this latter genus have an excipulum of loosely woven, hyaline, pachydermatous hyphae which spread laterally to form a conspicuous white border to the apothecium. However, some specimens of B. subdiscordans (Nyl.) P. James, when growing on bark, mosses, or rocks, do not have conspicuous whitebordered apothecia, although the pachydermatous hyphae are clearly seen in sections of the apothecia. Lignicolous members of the 'Lecanora' symmicta group are occasionally confused with Micarea species on account of their general appearance and excipulum structure. Their excipular hyphae are radiating, richly branched and anastomosed and lax in K, although they contrast markedly with the simple or sparingly branched paraphyses and do not give the impression of being 'paraphysis-like'. This group further differs from Micarea in having dense epithecial granules which dissolve in K and a generally different suite of Uchen substances (which includes usnic acid and zeorin). Another seemingly distinctive group of species (but not yet afforded generic status) that bears some close resemblances to Micarea is that containing such species as Catillaria contristans, Lecidea limosa, and L. stenotera; for further discussion see account oi Micarea assimilata (p. 115). The apothecia of Vezdaea species are superficially similar to those of some species oi Micarea, but differ in that their tissues are not bound by a gelatinous matrix and their asci have uniformly amyloid walls and do not belong to the Lecanora-type; see Poelt & Dobbeler (1975). There has been some confusion between Micarea and genera such as Arthonia Ach., and Chrysothrix Mont., and also the Trapelia-\ike 'Lecidea' granulosa group. These all differ from Micarea in not having Lecanora-typc asci (see 'Excluded taxa'). Suprageneric considerations The formulation of a ± stable hierarchical classification of fungal (including lichen) taxa above the rank of genus is unUkely to be achieved for some decades. A suprageneric classification for the lichenized fungi has been attempted in recent years by, for example , Henssen & Jahns (1973) and Poelt (19746). These schemes are extremely useful bases for further study but, as admitted by their authors, contain very many uncertainties and points of conjecture, and should be regarded as being of a very provisional nature. Micarea has Lecanora-type asci and clearly belongs in the order Lecanorales and suborder Lecanorineae as defined by Poelt (19746). My belief is that Micarea should be placed in the Lecideaceae Chev. s. sir. (i.e. confined to species with Lecanora-type asci), with the provision that the real differences (if any) with that family and the Lecanoraceae Fee need to be explored. For the time being (at least) I cannot accept the 'Micareaceae Vezda ad int.' (Poelt, 19746: 627; Eriksson, 1981), although it may be possible to formally define this family name in the future as knowledge and taxonomic concepts in the Lecanorales increases and advances.
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20 BRIAN JOHN COPPINS Micarea The g
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22 BRIAN JOHN COPPINS Morphology Th
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32. Micarea osloensis (Th. Fr.) Hed
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34. Micarea prasina Fr. LICHEN GENU
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conferanda (Lecidea) 205 confusula
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populina (Lecidea, Micarea) 31,32 p
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