Peltigera Explained

Peltigera is a genus of approximately 100 species of foliose lichens in the family Peltigeraceae. Commonly known as the dog or pelt lichens, species of Peltigera are often terricolous (growing on soil), but can also occur on moss, trees, rocks, and many other in many parts of the world.^[1]

Most species of Peltigera have the cyanobacterium Nostoc as the dominant photobiont but some have the algae Coccomyxa. The presence of both a green alga and a cyanobacterium makes some tripartite; in this case they show cephalodium growths containing the third partner, Nostoc. Because of their ability to fix nitrogen from the atmosphere, such lichens are influential in soil composition and generation.

Description

Species of Peltigera are foliose, with broad lobed thalli. Although the size of the thalli is variable and species-dependent, in some species the thalli can grow quite large, up to 30 cm in diameter.^[2] The color of the upper surface may range from drab gray, brown or greenish. Lower surfaces are typically without a cortex (unlike other foliose lichens),^[3] and cottony, often with fungal hyphae fused to form a network of veins. The reproductive structures isidia, soredia or may be present in some species.^[4] All species of Peltigera associate with the nitrogen-fixing cyanobacteria Nostoc.

Peltigera can be distinguished from the equally large and leaf-like lichen, Nephroma, by its veined lower cortex; Nephroma, by contrast, has a smooth, unveined lower cortex.^[5]

Habitat

Peltigera are mainly ground-dwelling, but can also be found on mosses or dead wood. Some species are used as forest succession indicators.

Taxonomy

In 1753, Linnaeus first described the species Lichen apthosus and L. caninus back when all known lichens were grouped into the genus Lichen.^[6] Later, in 1787, Willdenow circumscribed the genus Peltigera, and redescribed P. aphthosa and P. canina.^[7]

The generic name is derived from the Latin language pelta (small shield), and refers to the shield-shaped thallus in these species. The common name, the dog lichen, refers to the perceived resemblance of P. caninus to a dog.^[8]

Phylogeny

In a comparative analysis of both morphological and chemical characteristics as well as sequences of large subunit nuclear ribosomal DNA, it was shown that the genus Peltigera is monophyletic.^[9] Several species, such as P. canina, have been changed to a group as there appears to be several species clustered under a single name.

Distribution

The Peltigera have a widespread distribution, and are found on all continents. There are 34 North American species, 30 European species, 25 species from South America, and 16 species from New Zealand.^{[2] [10] [11]} There are 27 Peltigera species that have been recorded from China.

Species

• Peltigera alkalicola – Tanzania
• Peltigera aphthosa
• Peltigera appalachiensis
• Peltigera aquatica
• Peltigera asiatica
• Peltigera borealis
• Peltigera borinquensis
• Peltigera britannica
• Peltigera canina
• Peltigera castanea
• Peltigera chabanenkoae
• Peltigera chionophila – North America
• Peltigera cinnamomea – northwestern North America
• Peltigera clathrata
• Peltigera collina
• Peltigera degenii
• Peltigera didactyla
• Peltigera dilacerata
• Peltigera dolichorhiza
• Peltigera elisabethae
• Peltigera elixii
• Peltigera esslingeri
• Peltigera evansiana
• Peltigera extenuata
• Peltigera fibrilloides
• Peltigera fimbriata – Papua New Guinea
• Peltigera flabellae
• Peltigera frigida
• Peltigera frippii – Norway
• Peltigera gallowayi
• Peltigera gowardii – northwestern North America
• Peltigera granulosa – Papua New Guinea
• Peltigera hawaiiensis
• Peltigera hokkaidoensis
• Peltigera holtanhartwigii
• Peltigera horizontalis
• Peltigera hydrophila – Chile
• Peltigera hydrothyria
• Peltigera hymenina
• Peltigera isidiophora – China
• Peltigera islandica – Iceland
• Peltigera itatiaiae
• Peltigera koponenii – Papua New Guinea
• Peltigera kristinssonii – Iceland
• Peltigera kukwae
• Peltigera lactucifolia
• Peltigera lairdii – Antarctica
• Peltigera latiloba – Alaska (USA); Norway
• Peltigera lepidophora
• Peltigera leptoderma
• Peltigera leucophlebia
• Peltigera malacea
• Peltigera massonii
• Peltigera melanorrhiza
• Peltigera membranacea
• Peltigera mikado
• Peltigera montis-wilhelmii – Papua New Guinea
• Peltigera neckeri
• Peltigera neodegenii – China
• Peltigera neopolydactyla
• Peltigera neorufescens
• Peltigera nigriventris
• Peltigera occidentalis
• Peltigera orientalis
• Peltigera pacifica – Canada
• Peltigera papuana – Papua New Guinea
• Peltigera phyllidiosa
• Peltigera polydactylon
• Peltigera ponojensis
• Peltigera praetextata
• Peltigera pulverulenta
• Peltigera pusilla
• Peltigera rangiferina
• Peltigera retifoveata – Finland
• Peltigera rufescens
• Peltigera rufescentiformis
• Peltigera scabrosa
• Peltigera scabrosella – Norway
• Peltigera seneca
• Peltigera serusiauxii
• Peltigera shennongjiana – China
• Peltigera sipmanii
• Peltigera sorediifera
• Peltigera stanleyensis
• Peltigera subhorizontalis
• Peltigera tartarea
• Peltigera tereziana
• Peltigera ulcerata
• Peltigera vainioi
• Peltigera venosa
• Peltigera vitikainenii
• Peltigera weberi – Papua New Guinea
• Peltigera willdenowii
• Peltigera wulingensis – Canada; China; Norway; Russia

Uses

Peltigera species have been used historically to treat wounds, urinary disorders, thrush, tuberculosis, and rabies.^{[8] [12] [13]} P. apthosa was used as a remedy for cough^[14] and infantile aphthae.^[15] P. furfuracea has shown potent antioxidant activity and reducing power.^[16] Similarly, Peltigera specimens from Hawaii and Iceland have also been reported to show pronounced antioxidant activity.^[17]

Food source

Although a few reports have described caribou and reindeer feeding on the thalli of Peltigera,^[18] in general, species of Peltigera are not commonly used as a food source by mammals.^{[19] [20]} A study of the grazing habits of the land snails Cantareus aspersa and Limax species revealed that these snails prefer to eat Peltigera species (such as P. praetextata) that are lacking in secondary metabolites.^[21]

Bioactive compounds

Peltigera leucophlebia contains the compounds tenuiorin and methyl orsellinate, which are inhibitory to the enzyme 15-lipoxygenase.^[22] Tenuiorin is also known to occur in P. apthosa, P. malacea and P. neckeri.^[23] A mixture of methyl and ethyl orsellinates have been identified from P. aphthosa that had antibacterial activity against Gram-positive and -negative bacteria.^[24] The novel non-protein amino acids solorinine and peltigerine have been detected in various species of Peltigera.

Further reading

Gilbert, O. Lichens Naturally Scottish. 2004. Scottish Natural Heritage.

Notes and References

1. Martinez I, Burgaz AR, Vitikainen O, Escudero A . 2003 . Distribution patterns in the genus Peltigera Willd . The Lichenologist . 35 . 4. 301–323 . 10.1016/S0024-2829(03)00041-0.
2. Vitikainen O. (1994). (1998). Taxonomic notes on neotropical species of Pelitgera. In: Lichenology in Latin America: history, current knowledge and applications. Edited by M. P. Marcelli, and M.R.D. Seaward. CETESB, Companhia de Tecnologia de Saneamento Ambiental, Estado de Sao Paulo. pp. 135-139.
3. http://www.lichens.lastdragon.org/faq/lichenthallustypes.html#foliose Fioliose lichens, Lichen Thallus Types, Allan Silverside
4. Book: Geiser, Linda . McCune, Bruce . Macrolichens of the Pacific Northwest . Oregon State University Press . Corvallis . 1997 . 198 . 0-87071-394-9 .
5. Web site: CNALH - Peltigera. 2021-03-22. lichenportal.org.
6. Linnaeus C. (1753). Species plantarum. Stockholm.
7. Willdenow 1787
8. Book: Sharnoff, Stephen . Brodo, Irwin M. . Sharnoff, Sylvia Duran . Lichens of North America . Yale University Press . New Haven, Conn . 2001 . 0-300-08249-5.
9. Miadlikowska J, Lutzoni F . 2004 . Phylogenetic classification of peltigeralean fungi (Peltigerales, Ascomycota) based on ribosomal RNA small and large subunits . https://web.archive.org/web/20200626164420/http://pdfs.semanticscholar.org/ade6/50e695f3a147e8468be5ee96bc0c7d801f5d.pdf . dead . 2020-06-26 . American Journal of Botany . 91 . 3. 449–464 . 10.3732/ajb.91.3.449 . 21653401.
10. Goward T, Goffinet B, Vitikainen O . 1995 . Synopsis of the genus Peltigera (lichenized Ascomycetes) in British Columbia, with a key to the North American species . Canadian Journal of Botany . 73 . 91–111 . 10.1139/b95-012 .
11. Galloway DJ . 2000 . The lichen genus Peltigera (Peltigerales:Ascomycota) in New Zealand . Tuhinga . 11 . 1–45 .
12. Negi HR, Kareem A . 1996 . Lichens: the unsung heroes . Amruth . 1 . 4. 3–6 .
13. Book: Moerman, Daniel E. . Native American ethnobotany . Timber Press . Portland, Or . 1998 . 0-88192-453-9 .
14. Perez-Llano GA . 1944 . Lichens. Their biological and economical significance . Botanical Review . 10 . 27–40 . 10.1007/bf02861799.
15. Vartia KO. (1950). On the medicinal use of lichens. Academic dissertation. Helsinki: 11–21.
16. 15752633 . 10.1016/j.fitote.2004.05.012 . 76 . 2 . Antioxidant activity, reducing power and total phenolic content of some lichen species . March 2005 . Fitoterapia . 216–9 . Odabasoglu F, Aslan A, Cakir A, etal .
17. 25808912 . 10.1111/1462-2920.12850 . Comparative analysis of the antioxidant properties of Icelandic and Hawaiian lichens . March 2015 . Environmental Microbiology . 18 . 8 . 2319–25 . Hagiwara K, Wright PR, etal .
18. Palmqvist K . 2000 . Tansley Review No. 117. Carbon economy in lichens . New Phytologist . 148 . 1 . 11–36 . 10.1046/j.1469-8137.2000.00732.x . 33863029 . free .
19. Maser Z, Maser C, Trapper JM . 1985 . Food habits of the northern flying squirrel (Glaucomys sabrinus) in Oregon . Canadian Journal of Zoology . 63 . 5. 1084–1088 . 10.1139/z85-162 .
20. Kallman S . 1992 . Wild plants as food during survival situations . Sven Bot Tidsk . 86 . 2. 49–52 .
21. Benesperi R, Tretiach M . 2004 . Differential land snail damage to selected species of the lichen genus Peltigera . Biochemical Systematics and Ecology . 32 . 2. 127–138 . 10.1016/S0305-1978(03)00141-8 .
22. Ingólfsdóttir K, Gudmundsdóttir GF, Ogmundsdóttir HM, Paulus K, Haraldsdóttir S, Kristinsson H, Bauer R . Effects of tenuiorin and methyl orsellinate from the lichen Peltigera leucophlebia on 5-/15-lipoxygenases and proliferation of malignant cell lines in vitro . Phytomedicine . 9 . 7 . 654–658 . 2002 . 12487331 . 10.1078/094471102321616481.
23. Holtan-Hartwig . J. . 1993 . The lichen genus Peltigera exclusive of the P. canina group, in Norway . Sommerfeltia . 15 . 3–77 . 10.2478/som-1993-0001 . free .
24. Ingólfsdóttir K, Bloomfield SF, Hylands PJ . In vitro evaluation of the antimicrobial activity of lichen metabolites as potential preservatives . Antimicrob. Agents Chemother. . 28 . 2 . 289–92 . 1985 . 3834834 . 180233 . 10.1128/aac.28.2.289.