Key to the genera of the Lichinaceae

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Lichenologist 34(1): 39~62 (2002) doi:l0.l006/lieh.2001.0367,

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Key to the genera of the Lichinaceae Matthias SCHULTZ and Burkhard BÜDEL Abstract: A key is provided to all genera currently included in the cyanobacterial lichen family Lichinaceae as weil as some close relatives. Characteristic features of the family are described and illustrated. i!J2002 The Britishlichen Society

Introduction Approxima.telyl 250 species in c. 35 genera are eurrently reeognized in the cyanobaeterialiichen family Lichinaceae (Liehinales), and the cireumseription of the genera is a major ehallenge when studying the family. Some genera are very similar and difficult to separate Ce.g. Anema and Phylliscum macrosporum-group); others appear to be heterogeneous beeause of eonsiderable differenees between the species Ce.g. Lempholemma, Lichina,' Lichinodium, Pterygiopsis). These problems were the subjeet of reeent studies on phylogenetie relationships in the Lichinaceae and its elose relatives (Sehultz 2000). The aim of the present paper is to provide a key for the determination of all genera of the Lichinaceae including Gloeoheppia of the Gloeoheppiaceae and Heppia which was reeently shown to be closely related to the Lichinaceae CSehultz 2000; Sehultz et al. 2001). Materials

More than 2000 specimens, including 73 types, were studied. Speclmens were borrowed or seen from the following herbaria and collecrions: ASU, B, BM, CANB, COLO, DUD, F, G, H-NYL, HAL, HBG, M, MB, MIN, MUB, 0, PC, RB, S, TNS, TUR, UPS, WU; G. Brown (Roswck), B. Büdel (Kaiserslautern),

0024-2829/02/020039+24

Fanrlly characteristics The following overview of charaeter variation in the family is largely in aeeordance with the observations presented in earlier works (e.g. Henssen 1963, 1979; Henssen et al. 1981, 1987; Moretlo 1988; Moreno & Egea 1991). Morphology

and Methods

M. SchuIz and B. Büdel: FE Biologie, Abt Allgemeine Botanik, Universität Kaiserslautern, Postfach 3049, D-67653 Kaiserslautern, Gerrnany.

G. Ernst, A. Frisch (Bayreuth), L. Garvie (Tempe), V. John (Bad Dürkheim), B. Mies (Duisburg), S. Porembski (Rostock), C. Printzen (Bergen), B. Ryan (Tempe), W. B. Sanders (Recife), C. Scheidegger (Birmensdorf), M. Schultz (Kaiserslautern), M. R. D. Seaward (Bradford) and G. Willems (collecrion B. Büdel). Cryotome secrions (16-20I1m thick) were stained with lactophenol cotton blue. Anawmieal measurements were made using semi-permanent mounts. lodine reactions were tested after pretreatment with KOH. Micrographs were taken with a Zeiss Gena) Axioskop compound miero.cope using DIC. Micrographs were taken with a Nikon F3 camera with a Zeiss Luminar 40 mm lens mounted on bellows.

of the vegetative

thallus

The thalli are usually very small. Spreading erusts may cover several square eentimettes, whereas isolated squamules or cushions often measure only 0'5-5 mm. Compound, foliose to frutieose thalli may reach more than 2 em in size, but these are rare. Among the largest and most eonspicuous species are Lichina pygmaea C. Agardh (Fig. lA), Thyrea latissima Asah., Digitothyrea spp. (Fig. 2A & B), Lichinella cribellifera

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Key ro the genera of the Lichinaceae--Schu/tz & Bilde!

(Ny!.) P. Moreno & Egea, L. nigritella (Lettau) P. Moreno & Egea (Fig. 2F), Palt/ia pelforata (Pers.) Asah. and Jemmania goebe!ii Wächter (Fig. 2H). The pigmentation ofthe gelatinous sheath of the phorobiont cells in the outer parts of the thallus is responsible for the blackish colour of the lichens. However, in crosssection the gelatinous sheaths are yellowish brown owing ro the presence of the cyanobacterial pigment scyronemin or reddish ro purplish due ro the presence of gloeocapsin. Occasionally the thalli are whitish, greyish or bluish pruinose [e.g. iVletamelanea caesiella (Th.Fr.) Henssen (Fig. 4J), Psorotichia dijfracta (Ny!.) Forssell, Anema decipiens (A. Massa!.) Forssell (Fig. 3F), Thyrea confusa Henssen, Thyrea girardi (Durieu & Mont.) Bag!. & Carestia (Fig. 2D)]. Almost all types of growth form are known in the Lichinaceae (Figs 1-4). Fruticose species include Lichinella stipatula Ny!. (Fig. 3H), Digitothyrea divergens (Henssen) P. Moreno & Egea (Fig. 2A), Paulia caespitosa Tretiach & Henssen and most of the Peccania (Fig. 1C) and Synalissa species. A filamentous growth form is presenr in Ephebe (Fig. 1E & F), Zahlbrucknel'ella (Fig. IH), Lichinodium and Therrnutis (Fig. IG). Foliose thalli are formed in, for example, Llchinella cribellijera, Thyrea girardi (Fig. 2D) and Digitothyrea rotundata (Büdel, Henssen & Wesseis) P. Moreno & Egea. Squamulose thalli are formed in Anema decipiens (Fig. 3F), Phylliscidium 11'lonophyllurn (Kremp.) Forssell (Fig. 3E), some Pte1ygiopsis and Phylliscum species (Fig. 3A) as weil as in Gloeoheppia (Fig. 3G & H) and Heppia (Fig. 31 & J). Crusrose thalli are present in Ciyptothele, pyrenopsis (Fig. 4E), Lernmopsis, some species of Lernpholernrna, P01'ocyphus (Fig. 4F), Ptelygiopsis (Fig. 4D), Stromatella

(Fig. 4H), lvletamelanea (Fig. 4J & K) and in Psorotichia (Fig. 41). The thallus surface is smooth, warty or variously folded. Regularly tessellate surfaces are presenr in some species of pazZ/ia (Fig. 3C), Phylliscwn (Fig. 3A) and Phyllisciella. Soralia are very rare, but occur at the margins of squamules of Gloeoheppia erosa (Fig. 3G) and Heppia cOllchiloba Zahlbr. Isidia are globose (Fig. 2F), scale-like, cylindrical or coralloid, ecorticate outgrowths of the thallus surface. Anatomy

01' the vegetative

thallus

The thallus is gelatinous when wet with the symbionrs embedded in a conrinuous gelatinous matrix (Fig. 5A, D & F). When moistened, the thallus colour remains almost unchanged or changes slightly from jet-black to blackish olive, blackish purpIe or blackish brown. Subgelatinous thalli are not jet-black, being usually tinged brownish, olive or dark reddish. When moistened, the thallus colour often turns distinctly lighter. A conrinuous gelatinous matrix is usually lacking in subgelatinous thalli; instead, small or sometimes larger, air-filled caviries are formed (Fig. 5G & H). Subgelatinous thalli are rare, being found in Gloeoheppia, Heppia, Phylliscum japonicurn Zahlbr. and an undescribed species from the Sonoran Desert resembling certain members of Pterygiopsis. Thalli are not stratified (i.e. they are homoiomerous, Fig. 5A & B), or they may have a central cord of loosely or densely aggregated hyphae (Figs 5D & E, 6D). Sometimes, the cenrral cord is fountainlike [Lichina spp. (Fig. 5C), Lichinella stipatula, L. robusta Henssen]. Tmly stratified, heteromerous thalli occur exclusively in

FIG. I. Thallus morphology in Ihe Liehi"aceae: growIh form fruIicose (A-D & I), filamenrous-fruÜcose dominared by Ihe shape of Ihe phorobiol1t (E-H). A, Liehina pyg1l1aea,lobes flatIened ro davate (SchullZ 04(11); B, Liehina contillis, lobes IereIe (Schutz:; 04015a); C, Peccallia coralloides (Sehultz 16076b); D, 'Pcccania' salevensis, lobes club-shaped, pruinose (G-lecIOIype); E, t-:phebebrasiliensis,phorobiol1t Sl(gonema (B 41324); F, Ephebe penpinulosa, photobiom Stigone1l1a:Ihallus filamenrs wiIh numerous Ün)' side branches (Schult::; 13126a); G, ThemiUtis velwilla, photObiol1t Sc)'wllema, single apoIhecium (arrow) (Sehultz 13125a); H, Zahlbruclmerella paragonica, photObionI Scyzollema, numerous apoIhecia (M 0024053-isot)'pe); I, Lichilldla rob.ma, richly branched lobes (B 75321). Scales: A-C=IO 111111; D-I=5 mm.

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Key to the genera of the Liehinaeeae-Sehultz;

Heppia (Fig. 5G), bUt a distinct medulla is lacking. Corticate thalli are presem only in Liehina pygmaea, Jemmania goebelii (Fig. SE) and species of Heppia (Fig. 5G), except H. lutosa (Ach.) Ny!. (Henssen 1994). The general anatomieal arrangement of the symbionts is often paraplectenchymatous with small, roundish or angular fungal cells (e. 5 ).Im), and small photobiont cells (e. 5-7'5 firn) with a thin gelatinous sheath (Figs SF, 6F & G, 8D). The fungal cells are often elongated (e. 5-10 x 1.5-2,5 j.,Im) in thalli with a loose, rericulare anatomy and the phorobiont cells are usuaJ1y larger (7'S-20 firn) and surrounded by a thick gelatinous shearh (e.g. Anema, Paulia, Phylliseum, Phyllisciella, S,vnalissa, Figs 5A & B, 6G). A fan-Eke arrangement of hyphae is found in some Porocyphus species. The photobiom cells are arranged in :!:vertieal rows in rhe paraplectenchymatous thalli of Pterygiopsis (Fig. 5F). The thalli are fastened ro sofr subsrrata by rhizohyphae rhat originare from the entire lower surface (Fig. 5G) or by tUfts of such hyphae. Thalli growing on hard rock are often affixed by a gelatinous basallayer, by a small umbiEcus (Fig. 2B) or by a short stalk. Ascoma

anatomy

The apothecia have open, flat, urceolate or punctiform dises. In the latter case they are perithecioid in oUtward appearance [e.g. Phylliseum demangeonii (Moug. & Mont.) Ny!. (Fig. 3A)]. The apothecial srructure mal' vary considerably during development, and often rhe differences in the ascomatal onrogeny are obscured in mature apothecia. Juvenile stages are needed ro determine the type of ascoma omogeny.

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The apothecial margin is usually zeorine (as defined by Henssen & Jahns 1973) (Fig. 6F & G). However, the thickness ofrhe proper and thalline margins can vary considerabll'. Juvenile apothecia of Porocyphus usually possess a thin, tme exciple, whieh becomes thicker with age as the thalline margin recedes. In such cases the proper exciple is visible as a pale ring surrounding rhe apothecial disco The proper exciple is usuaJ1y composed of a few rows of loose1y inrelwoven, thin, e10ngated or :!:isodiametric hyphae that largely resemble thallus hyphae (e.g. Ane11la, Thyrea, Pyrenopsis). Occasionalll', the hyphae ofthe proper exciple are strongll' ge1atinized and differ from normal rhallus hyphae [e.g. Lemmopsis spp., Gloeoheppia spp., Thermuris 'velutina (Ach.) Flot.]. Rarely, rhe rrue exciple is lacking [e.g. Peecania spp. (Fig. 6D), Psorotiehia spp. (Fig. 6C), Paulia]. Similarly, absence of a thalline exciple is uncommon; examples are Lichinodium ahlneri Henssen, Thermutis velutil'la and lVletamelanea in which rhe ascoma initials are not surrounded by thalline tissuc. Asconla ontogeny Ascoma deve10pmem is ascohymcnial and hemiangiocarpous with ascogoncs ami trichogl'nes. Henssen (1963) described three main types of ascomaral developmem in the Liehinaceae: a rangle of generative hl'phae with ascogones and trichogynes (Fig. 7F & G), pl'cnoascocarps (Fig. 7H & I) and rhallinocarps (Fig. 7C-E). According to our results the main deve10pmental types are constanr within species; however, imermediate rypes were reported by Henssen (1963,1973). Table 1 gives an overview of

1OIG.2. Thallus morphology in rhe Lichinaceae: growrh form fuliose-fruricose (A-C & E-H), growth form foliose (D). A, Digiunhyrea divergellS,lobes erecr and tongue-shaped (Schuh=:14001); B, Digirvthyreapolyglossa, lowcr sidc of rosene-shaped lhallus (BÜde/20 141b); C, ']emnania' osol1.oi,srrap-like, twisted lobes (M 0023944-isorype); D, Thyrea girardi, lobes broad and denseJy pruinose (B 81300); E, Phy/liscum japonicum, lobes hollow (arrow) and aporhecia wirh pWlcriform discs (B 68); 10,Lichine/la nigrite/la, lobe surface rough due to numcruus globose isidia (Schuhz 17036a); G, 'Goilohymonia' uudu!"'a, lobes lmdularing and erecr (M 0023702-isorype); H, ]ellmanw goebelii, suap-like lobes, consrricted ar their base (AL Kato: TNS). Scales: A-D & F-H= 10 mm; E=5 mm.

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Key to rhe genera of rhe Lichinaceae-Schu/rz TABU

I, A5coma ontogmy

il/ the Liehinaeeae:

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",ain rypes and 50llze vw'iatio1l5 Variams

Type I, tangle

spheroid tangle of generative hyphae with aseogones and triehogynes (Fig, 7F)

aseogones and triehogynes arising treely in the thallus (Fig. iG)

2. pyenoaseoearp

aseogones formed in a tangle-like struetUre beneath quiekly degenerating pyenidia (Fig. 7H); juvenile asei usually do not enter the pyenidial eavity

ascogones and trichogynes arising freely beneath pycnidia when conidia are s,ill formed, elongated conidiophores (Fig, 8.'1.) functioning as primary paraphyses, renmants of eonidiophores often visible when first asci arise (Fig. 8B)

3. thallinocarp

aseogones and triehogynes arising freely (Fig. 7D), tangle is redueed, asei and few paraphyses ftee beneath the:!o elosed thallinoearp surface, or hymenium covered by small thallus portions

aseogones and triehogynes arising freely, tangle is reduced, partial hymenia are formed (Fig, 7E), i.e. sm all paekets of asci and paraphyses are marginally separared by sterile thallus tissue and penetrate the thallinocarp surfaee with a tiny punctiform dise

the aseoma onrogeny including within the main types.

variations

Asci and ascospores The majority of the Lichinaceae possess prototunicate asci with a thin, one-layered, non-amyloid wall (Fig. 8G-I) and passive spore diseharge via apieal rupturing. This type of aseus wall opening is not in aeeordanee with the definition of the prototunieate aseus, i.e, the emire aseus wall disinregrates. Nevertheless, the. term prorotunieate is widely used tor the type of aseus in the Lichinaceae. There are minor ditferenees in the wall thiekness, the shape of the aseus itself and the presenee, thiekness and amyloidity of an oUter gelatinous eoat. Moreno & Egea (1991) deseribed several subtypes based on light mieroseopy observations. Transmission eleetron microseopy of prototunieate asci in Anema nummularium (Duf. ex Durieu & Mom.) Ny!. ex Forssell (B.

Büdel, unpublished data) and Heppia lutosa (Büdel 1987) revealed no struerural ditferenees. Henssen et al. (1987) showed that the unitunieate-rostrate aseus type is present in Euopsis, Harpidium (Fig. 7B) and species of Pyrenopsls (Fig. 8J). Ir ditfers from the prototunicate type in strueture and timetion with the spores being released actively through a protruding rostrum. The aseus wall is thicker, and the inner layer is expansible and amyloid. Ascus shape varies from cylindrical to narrowly or broadly clavate. The size rarely exceeds 100).tm in length and 25).tm in width. The aseus apex is usually rounded (Fig. 8H & I). Exeeptions with poimed aseus tips oecur in the PhylÜscum demangeonii group and in C/yptothele. In Lichinella the aseus shape is rather irregular (Fig. 7C & E). The ascospores are simple and hyaline (Figs 6G, 8F, G & J), although plasma

FIG, 3. Thallus morphology in the Lichillaceae: growth form squamu]ose. .'1., Phyl!ÜculIIdemallgeollii, thallus rosette-shaped, with slightly elongated lobules at the margin, surface tessellate, apothceial dises punctifonn (Ir'ermore390.B; AHN); B, Thelignyaligl~vvra,tiny squamules with immersed apotheeiu (arrow) ami umbonate dises (Schultz 13009a); C, Paulia schroederi,squamules buJging and tesseHate (WU 3733--holorype); 0, 'SYllalis5a' l/iEidltl",juvenile thaHus (G-hoJotype); E, Phyl!iscidiltlll monophyllum, small squamules, in part with e!figurate margins (Biidel 24070e); F, Allema decipzelt5,squamules pruinose (Sc/ndrz 14003c); G, Gloeohcppia .rosa, margins eroded-sorediate (Sc/witz 14010d); H, Gloeoheppia ",rgida, intiated squamules (Schultz 140101) und Lichillel!a sriparula,thallus dwarf-fruticose (.,'chltltz 14010c); I, Heppia despreauxii, Iht, rosette-shaped thallus, surface whitish pruinose, cracked and dotted (Schult:: 14004a); J, Heppia solorinoides,upper thallus surface wirh thiek, cracked, epinecrallayer (Schltlt:; 140131). Scales: A-E & J=5 mm; G-I=2',} mm.

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Key to the genera of the Liehinaeeae-Sehultz

bridges giving the spore the impression of being 2-eelled oeeur frequenrly. True septa were reporred in Gloeoheppia (Henssen 1995), however, after examining a large number of sampies of the genus, no septa were observed by uso The spore shape varies from globose, broadly or narrowly ellipsoid ro bean-shaped or falcate. The apiees are usually rounded but rarely somewhat pointed. Although dimensions range from 5-25(-30) ~m in length and 2,515 (-20) ~lm in width, the predominant spore size is e. 7, 5-15 x 5-10 11m, and the length: width ratio rarely exeeeds 2:1. The spore wall is usually thin, but rarely ir is up ro 2'5-4(-5) ~lm thick [Paulia spp. (Fig. 8F), Pyrenopsis spp.]. Eight-spored asei predominate (Anema, Paulia, Peeeania). However, polyspory (16-32) is widely distributed (Liehinella, Zahlbrueknemlla, Ephebe, Phloeopeccania, Phylliseum, Pyrenopsis, Pterygiopsis, Cryptothele), but it does not exceed 32 as it does in Peltula (Lichinales, Peltulaceae). The spore number is apparenrly variable within the genera, but it seems to be eonsranr at speeies level. Variable spore numbers within. speeies are very rare (e.g. Phylliseum demangeonii, Phloeopeccania pulvinulina J. Stein er) . Conidiomata The pycnidia belong to type I (Lee anaclis) or type II (Roccella) (Vobis 1980). The pycnidial wall is hyaline (Fig. 8D) eonsisting of a few imerwoven hyphae. The shape of the pycnidia ranges from globose to pyriform or ovoid. Oecasionally the wall is convoluted

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(Fig. SC) giving the pycnidial eavity a cerebriform appearance (e.g. Liehina pygl1laea, Heppia spp.); the size is approximately 50-200 11m. The ostiolum and/or the emire pycnidial wall are rarely dark-coloured [Thelignya, Thermutis, Zahlbrucknerella (Fig. 8C)]. The conidia are usually smalI, hyaline, ellipsoid or bacilliform, and measure 2-5 x 1-1'5 11m (Figs 7I, 8C & D); globose conidia are very rare (Thermutis velutina). The eonidia in Cryptothele, Peecania (Fig. 8E), Phylliseiella, Phylliscum demangeonii and Liehinodium ahlneli are filamentous, straight, falcate or sinuose, reaehing 15-40 11m in length. The conidia are formed terminally on simple or weakly branched conidiophores and belong ro type II (Vobis 1980). In Peccania the conidiophores belong ro type III and are terminally branched.

Photobionts The most common photobioms in the Liehinaceae are eoccoid cyanobacteria such as Chrooeoceidiopsis, Nlyxosareina (Büdel & Henssen 1983; Henssen & Büdel 1984) and Gloeocapsa. Among the filamemous cyanobacteria, Sligonema occurs in Ephebe (Fig. 6B), Scytonerna occurs in Thennutis, Lichl:rlOdium, Zahlbruclmerella (Fig. 6A) and Heppia (Henssen 1994) (Fig. 5G), species of the Rivulariaceae (Dichothrix, Calothrix) are found in Liehina (Fig. SC), Porocyphus and Calol1iehopsis, Nostoc occurs exclusively in Lempholernma (Fig. 7H), and Tolypothrix (J\llicrochaetaceae) OCCUl'S in Thennutopsis (Henssen 1990).

FIG. 4. Thallus morphology in the Liehirwecac: growth form squamulose-crustose w crustose. A, Glocohcppia po(yspora,thallus squamulose-crustose (SeI",Üz 16038a) and two cushions nf Liehillcllaamen'wllu (Selw!lz 16038b); B, A'lellta eC/'IIohorsl'yi,thallus erustose in surface view but composed of mnnerous smalI, stalked squamlÜes (Henssen, Lieh. cyall. fUllgi sax. exs. no. 47; M); C, Lcmpholel1lmapolyalllhes, irrcgularly shaped thallus on mosses with peritheeioid apathecia (G. Emse); D, PrerygiopsisguyallellSis, thallus arcolate, margin effigurate, apathecia sessile and in part umbanate (B-holotype); E, Pyrcllopsis tripweoeca, thallus granulose [() irregularly areo!ate, margins of young thalli effigurate (MUB 381); F, Poroeypl",s IwmllorellSis,rhallns irregularly effigurate (Henssen, Lieh. cyau. filllg; sax. exs. na. 45; ,v[); G, Phloeopeceaniapulvinuhua, thallus crustOsc in surface view but composed of numerous tiny cushions wirh short, compressed lobu!es, apothecia with depressed discs (Schult::;16106d); H, Stromate!!a beml1ldanu, thallus a,"eolare, surface of the areoies finely tessellate, apathecia scmi-immersed .md with erenare thalline margin (Schultz 1(0551); I, Psorotiehia l1Iurorum,thallus irregularly areolate, apathecia 2-5 per areoie (L. Garvie; ASIJ); J, lvletamelullea eaesiella, thallus rimase-arealate, surfaee pruinose and snmewhat pulverulent, apothecia immersed, dises open (Schultz 03166a); K, lvIetalllelanealIIelambola,thallus rirnose-areolate, apothecia immersed, dises open and becoming umbonate (BÜdel24061a). Seales. A-K=5 mm.

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Key to the genera of the Lichinaceae-Schulrz

The gelatinous sheaths of cells in the outer thallus layers are yellowish brown or reddish brown to purplish. The coloration is caused by cyanobacterial pigmenrs such as the alcyl indols, scyronemin or gloeocapsin. The pigmenrs are deposited as small granules in the gelatinous sheath, often arranged in conspicuous circles (Fig. 5A). Inside the thallus the gelatinous sheaths are usually hyaline. Molecular studies may help to estimate the variability of coccoid cyanobacterial photobionrs presenr in the Lichinaceae since the determination of the phorobionrs in a lichenized condition is prob1ematic and cultu re experiments are very time-consuming. Recently, molecular studies c1arified the idenrity of some of the phorobionrs in the Lichinaceae.' Chroococcidiopsis occurs in Palllia aldabrensis Henssen, as well as in three species of Lichinella (Jaeger 2000). These results were somewhat surprising since the shape of Chroococcidiopsis in the lichenized state was considerably differenr from that in free-living sampies or in cultured strains. Green algal phorobionrs are found only in three species. Harpidium rutilans Flor. ex Körb. and H. nashii Scheid. (Fig. 7B) possess a trebouxioid phorobiont. In EtlOpsis granatina (Sommerf.) Nyl., the green alga Trebouxia aggregata (Archibald) Gärtner occurs besides the primary cyanobacterial photobiont G!oeocapsa sanguinea (e. Agardh) Kütz emend. Jaag. (Büdel & Henssen 1988). Ecology and distribution Most types of lichen habitats are colonized, but only a few species are found on

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bark, twigs or on other lichens (Lecidopyrenopsis corticola Vain., Lichinodium spp.). Seepage tracks, rock pools and moist, steep rock faces are preferred habitats; bare soil is rarely colonized (Peccania spp.) Heppia spp., G!oeoheppia spp.). More frequently the species grow in sand-filled rock c1efts. A number of species occur in semi-aquatic freshwater habitats (Ephebe spp., Jemnania goebeHi, Ptelygiopsis spp., Thelignya lignyota (Wahlenb.) P. M. JfiJrg & Henssen). Lichina pygrnaea grows under saline conditions in the lower supralittoral (Balanoidal zone) of cool to temperate rocky seashores, whereas Lichina confinis e. Agardh is restricted to the upper supralittoral (wirh VemJcaria spp., Caloplaca 5pp.). In general, there seems to be a preference for basic substrata (e.g. limestone and calcareous soils). Lichinaceae occur worldwide in all c1imatic and orographie zones. Centres 'Ofdistribution are arid to semi-arid and Mediterranean regions. In humid or semi-humid tropical regions comparably dry microhabitats such as inselbergs are preferred (Büdel et al. 1994, 1997; Schultz er a!. 2000a). Endemism is not very pronounced probably due to the ubiquitous distribution of most of the cyanobacterial phowbionts. Some species may be considered a5 palaeoendemics; thus, most of the Pauha species colonize dry, tropical island or coasral habitats and have a disjunct worldwide distribution (Schultz er a!. 1999; Schultz er al. 2000b). Similar distribution patterns are known tor certain xerophytic mosses that presumably originated in tlle cenrre of the ancienr super-conrinenr of Pangaea (Frey & Kürschner 1988). The palaeoc1imate was

FIG. 5. Thallu, and aporhecial anaromy in rhe Liehilla,"ac. A, 'Peecall;a' salevellsis,thallus croöö-,ecrion, loosely rericulate anaromy and photobiont pigments deposired in the rhiek gelatinous shemh 01'the photobiont cells in the ourer rhallus part, (G---Iectotype); B, Phloeopceeall;apulv;nu!illa, eroöö-secrion 01'thallu, and juvenile apothecium, thicl< gelarinous shearh surrounding rhe rhallus, anaromy loosely rerieulare (SchulLz 14014a); C, Liehilla eOllfinis, lon!,"tUdinal thallus secrion, fountain-like, eompacr centra] cord (Schuh::: 13122); D, ']emllania' os",.i,'i, crossseerion 01'rhallus lobe, ecorticate and thin central srrand (M 0023944-isotype); E, .'lenlllamagoebelii,cross-section 01' thallus lobe, cortex 01' 1-2 rows 01'small, angular cells (arrow), strongly gclarinous central strand (kI. [(aw: TNS); F, PtCl}'giopsisguyal/ellSlS, cross-secrion 01'paraplectenehymarous thallus, rop: eells angular and in verrical rows, bottom: cells roundish (B-holotype); G, Heppw despreallxii, thallus cross-section, upper cortex of roundish eells and wirh epineerallayer, photobiont layer with thicl