Pannaria
Pannaria is a genus of lichen-forming fungi in the family Pannariaceae. These lichens form leaf-like, scaly, or crusty patches that typically arrange themselves in loose rosettes on tree bark in humid forests. Most species partner with nitrogen-fixing cyanobacteria, though some contain green algae instead. The genus was established in 1828 and now includes about 80 recognized species found worldwide, particularly in tropical and subtropical regions.
Description
Pannaria forms a thallus that can be leaf-like, a mosaic of tiny scales, or a thin crust. Many species arrange their lobes in loose rosettes and, unlike several related genera, they rarely develop the blue-black felt seen beneath other cyanobacterial lichens. The upper surface ranges from grey-blue to deep brown-black and may carry a light dusting of frost-like crystals. Most species partner with the filamentous cyanobacterium Nostoc, but members of the Pannaria sphinctrina group instead contain green algal cells.The lichen's sexual fruiting bodies are sessile apothecia whose red-brown to black are framed by a persistent rim of thallus tissue. That rim has two zones: an outer layer of tightly packed, brick-like cells and an inner layer that is looser and packed with cells. A thin, pale of cells surrounds the hymenium. The asci hold eight ascospores, show no blue reaction to potassium–iodide stain and lack the amyloid plug found in many related taxa. Their spores are colourless, single-celled, ellipsoidal and often end in one or two small points; the outer wall is finely warted or ridged.
Asexual reproduction is limited to scattered pycnidia that release straight, rod-shaped conidia. Thin-layer chromatography usually detects no secondary metabolites, though some species contain pannarin, which produces an orange-red colour with the para-phenylenediamine spot test.
Photobiont
Like most members of the Pannariaceae, species of Pannaria partner with filamentous, nitrogen-fixing cyanobacteria belonging to the genus Nostoc. A multilocus survey of 37 thalli representing 21 species showed that these are drawn from two broad Nostoc lineages previously known as the "Nephroma guild" and the "Peltigera guild"; the Pannaria sequences are scattered across both, with a gradual transition between them.Host choice is flexible. and species do not segregate cleanly by : some tripartite southern-hemisphere taxa share identical Nostoc strains with corticolous bipartite species from both hemispheres, whereas other Pannaria species show marked selectivity, keeping to a narrow subset of strains. This breadth of associations contrasts with the tighter photobiont fidelity reported for genera such as Nephroma and Peltigera.
Ecology
Species of Pannaria grow mainly as epiphytes on the bark of trees in sheltered, humid forests. They are encountered far less often on shaded rocks or on thin, moss-covered soil, where the micro-climate is similarly cool and moist.Species
, Species Fungorum accept 78 species of Pannaria:- Pannaria adpressa
- Pannaria aenea
- Pannaria andina
- Pannaria allorhiza
- Pannaria aotearoana
- Pannaria applanata
- Pannaria areolata
- Pannaria asahinae
- Pannaria athroophylla
- Pannaria atrofumosa
- Pannaria auctorum
- Pannaria brasiliensis
- Pannaria byssoidea
- Pannaria caesiocinerea
- Pannaria caespitosa
- Pannaria calophylla
- Pannaria cameroonensis
- Pannaria carneopallens
- Pannaria cassa
- Pannaria centrifuga
- Pannaria cheirolepis
- Pannaria chilensis
- Pannaria cinerascens
- Pannaria complanata
- Pannaria conoplea
- Pannaria contorta
- Pannaria craspedia
- Pannaria crenulata
- Pannaria crispella
- Pannaria crustata
- Pannaria decipiens
- Pannaria delicata
- Pannaria delisei
- Pannaria dissecta
- Pannaria durietzii
- Pannaria ekistophylla
- Pannaria elatior
- Pannaria elegantior
- Pannaria elixii
- Pannaria emodii
- Pannaria euphylla
- Pannaria exasperata
- Pannaria farinosa
- Pannaria fimbriata
- Pannaria flabellata
- Pannaria formosana
- Pannaria fulvescens
- Pannaria fumbris
- Pannaria funebris
- Pannaria gallowayi
- Pannaria glacialis
- Pannaria granulifera
- Pannaria globigera
- Pannaria holospoda
- Pannaria hookeri
- Pannaria howeana
- Pannaria hypnorum
- Pannaria immixta
- Pannaria implexa
- Pannaria insularis
- Pannaria isidiosa
- Pannaria italica
- Pannaria japonica
- Pannaria kantvilasii
- Pannaria kerguelensis
- Pannaria laciniata
- Pannaria laciniosa
- Pannaria lanuginosa
- Pannaria lasiella
- Pannaria lepidophora
- Pannaria leproloma
- Pannaria limbata
- Pannaria lobulifera
- Pannaria lurida
- Pannaria luridula
- Pannaria macrocarpa
- Pannaria malmei
- Pannaria mangroviana
- Pannaria melanesica
- Pannaria melanotricha
- Pannaria microphyllizans
- Pannaria minutiphylla
- Pannaria molkenboeri
- Pannaria molybdodes
- Pannaria mosenii
- Pannaria multifida
- Pannaria myrioloba
- Pannaria neocaledonica
- Pannaria nilgherriensis
- Pannaria obscura
- Pannaria oregonensis
- Pannaria pannosa
- Pannaria papuana
- Pannaria parmeliae
- Pannaria patagonica
- Pannaria perfossa
- Pannaria phloeodes
- Pannaria phyllidiata
- Pannaria placodioides
- Pannaria placodiopsis
- Pannaria planiuscula
- Pannaria prolifera
- Pannaria prolificans
- Pannaria pruinosa
- Pannaria pulverulacea
- Pannaria pulvinula
- Pannaria pyxinoides
- Pannaria ramosii
- Pannaria ramulosa
- Pannaria reflectens
- Pannaria rolfii
- Pannaria romanoana
- Pannaria rubiginea
- Pannaria rubiginella
- Pannaria rubiginosa
- Pannaria squamulosa
- Pannaria streimannii
- Pannaria subcrustacea
- Pannaria subfusca
- Pannaria subrubiginosa
- Pannaria subsimilis
- Pannaria superior
- Pannaria taylorii
- Pannaria tavaresii
- Pannaria tenuis
- Pannaria tetraspora
- Pannaria thoroldii
- Pannaria thraustolepis
- Pannaria tjibodensis
- Pannaria vischii
- ''Pannaria wrightiorum''