Punctelia rudecta | |
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In Cataloochee (Great Smoky Mountains), North Carolina; growing on the upper trunk of a red maple tree | |
Scientific classification | |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Lecanoromycetes |
Order: | Lecanorales |
Family: | Parmeliaceae |
Genus: | Punctelia |
Species: | P. rudecta |
Binomial name | |
Punctelia rudecta | |
Synonyms [1] | |
Punctelia rudecta, commonly known as the rough speckled shield or the speckleback lichen, is a North American species of foliose lichen in the family Parmeliaceae. This species can be readily identified by the light color of the thallus underside, the relatively large lobes at the edges of the thallus, and the tiny white pores present on the top of the thallus that are characteristic of the genus Punctelia . The lichen is quite abundant and widespread in the eastern and southeastern United States, although it also occurs in Canada and northern Mexico, but is less common in these regions. The lichen usually grows on bark, and less commonly on shaded rocks. There are several lookalike Punctelia species; these can often be distinguished from P. rudecta by differences in distribution or in the nature of the reproductive structures present on the thallus.
Although Punctelia rudecta was previously thought to have a much more expansive global distribution, phylogenetic analysis revealed a species complex that has subsequently been split into four distinct cryptic lineages with more restricted distributional ranges. Punctelia rudecta is moderately sensitive to air pollution and has been assessed as a suitable candidate for biomonitoring air quality.
Swedish lichenologist Erik Acharius described the lichen as a new species in 1814 as Parmelia rudecta. [2] The type specimen was collected by American clergyman and botanist Gotthilf Heinrich Ernst Muhlenberg. [3] Historically, Edward Tuckerman thought that the taxon was better suited as a variety of Parmelia borreri , [4] while Bruce Fink suggested that it should be a subspecies of that taxon. [1] In 1902, Antonio Jatta proposed a transfer to genus Imbricaria; [5] this genus name is no longer used for lichens and is considered a synonym of Anaptychia . [6] In a 1962 study of specimens named as Parmelia ruderata from Japan, William Culberson proposed that it be placed in synonymy with P. rudecta, [7] but this was not accepted by later workers and DNA evidence has since shown that Punctelia ruderata is an independent species. [8] In 1982, Hildur Krog circumscribed the genus Punctelia to contain Parmelia species with rounded pseudocyphellae, and P. rudecta was one of the 22 species transferred to the new genus. [9]
Parmelia rudecta is known colloquially as the "rough speckled shield" [10] [11] or the "speckleback lichen". [12] It has also been called the "backyard buddy", alluding to the relatively high chance of finding this lichen in a backyard in the eastern United States. [13]
A 2004 molecular phylogenetic study of Punctelia species in the Iberian Peninsula suggested that the taxon Parmelia rudecta did not form a monophyletic grouping, indicating that more than one species was being represented by the taxon. [14] This interpretation was later corroborated in a large-scale phylogenetic study of the family Parmeliaceae that was published in 2010. [15] A 2016 followup study of P. rudecta specimens from collections around the world confirmed the suspected cryptic diversity: there were four morphologically similar, but geographically isolated species that were all being called Parmelia rudecta. Three of these species were epitypified (P. rudecta in the strict sense, P. toxodes and P. ruderata), and a fourth, P. guanchica , was described as a new species. Because the original type specimen of P. rudecta was collected in North America, this name was kept for the North American species. The epitype used in the 2016 study was collected in Great Smoky Mountains National Park, North Carolina. [8]
The thallus of Punctelia rudecta ranges in color from dark greenish-gray to almost blue-gray; [10] it tends to be more gray-greenish when fresh, and more brown-yellowish when dry. [16] The thallus has a relatively tight attachment to its substrate. The lobes comprising the thallus are mostly 3–8 mm (0.1–0.3 in) wide, and are more or less covered with cylindrical to branched isidia; [10] the isidia are typically more numerous towards the center of the thallus. [11] Sometimes the isidia can become so dense that they form mounds, obscuring the lobes underneath. Both the margins of the lobes and the tips of the isidia have a brown tinge. [17] The lichen, when it has a bluish-green coloration and dense isidia, can be readily spotted from a distance. [11] White pseudocyphellae are usually prominent on the tips of the lobes. [10] The lower surface of the thallus is tan, with pale rhizines. Apothecia are uncommon. [10] If present, they are up to 4 mm (0.16 in) in diameter, with a brown hymenium and thin margin rolled inward. The ascospores measure 12.8–16 by 8–9.6 μm, and are ellipsoid in shape. They lack septa, and are smooth, thin-walled, and hyaline. [16] The photobiont partner is the green alga species Trebouxia anticipata . [18]
Standard chemical tests can be used to help identify Punctelia rudecta. In the medulla, these results are PD-, K-, KC+ red, and C+ red. The last of these tests indicates the presence of lecanoric acid. [10] The cortex contains atranorin, which results in a yellow K+ reaction. [11]
Punctelia rudecta is a member of a complex of several morphologically similar but geographically separated species. P. ruderata occurs in Asia and East Africa. P. guanchica, known only from the Canary Islands, grows on volcanic rocks. The South African member of the complex, Punctelia toxodes, grows on both tree bark and rocks. [8]
Punctelia eganii , known from a single locality in Alabama, USA, was described as a new species in 2011. Although morphologically identical to P. rudecta, it produces lichexanthone, a secondary compound previously unknown in Punctelia. This compound, which is present only in its pseudocyphellae, causes these structures to fluoresce when viewed under ultraviolet light and allow these otherwise identical species to be distinguished from each other. Two other similar species are P. missouriensis and P. punctilla ; these species are distinguished from P. rudecta by their propagules: they both produce ecorticate (without a cortex), scale-like soredia, structures that can be mistaken for isidia. [19] Specimens of P. rudecta that have few isidia can be mistaken for the southwestern speckled shield lichen, P. hypoleucites . This relatively rare species has a range restricted to Texas and Mexico. [10]
Punctelia rudecta has a temperate distribution in North America. [11] Although the range maps included in some popular North American lichen field guides suggest that it does not occur in the tropical climate of southern Florida, [10] [13] it was recorded in Fakahatchee Strand Preserve State Park in 2011. [20] It is occasionally recorded from western North America, but it is much less frequently encountered there. [17] [21] It grows on bark of all kinds, or on shaded rocks. Irwin Brodo calls it "one of the most common eastern isidiate foliose lichens", [10] while Erin Tripp and James Lendemer express similar sentiments about its prevalence, describing it as "arguably the weediest macrolichen east of the Mississippi River". In its range it grows in all types of forests, and at all elevations. [13] The lichen occurs in most Canadian provinces (Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec, and Saskatchewan). It has a national conservation status of "secure", and is "secure" or "apparently secure" in all provinces except Saskatchewan, where its status is "critically imperiled". [12] In Mexico, it has been reported from the Distrito Federal, Chiapas, Veracruz, Jalisco, [16] Baja California, Chihuahua, Durango and Sonora. [17]
Punctelia rudecta has an annual radial (i.e., expanding outward from the center) growth rate of about 5 mm (0.2 in) per year, similar to other foliose lichens in the family Parmeliaceae. [22] Ovicuculispora parmeliae (previously known as Nectria parmeliae) is a lichenicolous fungus that uses Punctelia rudecta as one of its many hosts. [23] [24] Laboratory studies established that this fungus is incapable of growing on Punctelia rudecta unless phenolic defense compounds are first removed from the lichen. In nature, O. parmeliae can grow on P. rudecta only after another lichen inhabitant, an epiphytic species of Fusarium , first enzymatically degrades lecanoric acid, the primary lichen compound of P. rudecta. Field studies demonstrated that lichens harboring N. parmeliae generally also harbor the Fusarium species. [24] Other fungal parasites that have been recorded growing on P. rudecta include Trichosphaerella buckii , Pronectria subimperspicua , [25] and an unidentified species of Cladophialophora . [26]
A study conducted in New York showed that Punctelia rudecta provides shelter for several species of mites; Carabodes higginsi , Phauloppia banksi , and an undetermined species of Anachipteria were the most numerous species encountered. The mites may help with the dispersal of lichen spores. [27]
Based on the frequency of Punctelia rudecta in heavily polluted areas, it is considered a relatively pollution-tolerant species, [28] although it is sensitive to ambient sulfur dioxide (SO2), and will not grow unless airborne SO2 concentrations are low. [29] It has been investigated for its potential use as an indicator of air quality in biomonitoring programs. To do this, the lichen is studied for effects on growth and for the accumulation of pollutants (such as toxic heavy metals) in the thallus, which, after collecting samples, can be determined in the laboratory with chemical techniques. [30] [31] [32] Punctelia rudecta is recommended for use as a biomonitor in the cooler forested uplands of Alabama, Georgia, North Carolina and South Carolina. [33]
Punctelia rudecta can be used to create a dye by a color-extraction with ammonia as a solvent. A pink color is obtained using this method. [34]
Punctelia is a genus of foliose lichens belonging to the large family Parmeliaceae. The genus, which contains about 50 species, was segregated from genus Parmelia in 1982. Characteristics that define Punctelia include the presence of hook-like to thread-like conidia, simple rhizines, and point-like pseudocyphellae. It is this last feature that is alluded to in the vernacular names speckled shield lichens or speckleback lichens.
Punctelia guanchica is a species of foliose lichen in the family Parmeliaceae that is only known from the Canary Islands. It is similar in appearance and morphology to the North American Punctelia rudecta, and was historically misidentified as that species until molecular phylogenetic evidence showed it to be a distinct species. It differs in having thicker isidia that develop from the centre of the pseudocyphellae, and it mainly grows on rocks.
Punctelia caseana is a species of foliose lichen in the family Parmeliaceae. Its range covers eastern North America, extending south to central and northern Mexico, where it grows on the bark of many species of hardwood and conifer trees.
Punctelia appalachensis, commonly known as the Appalachian speckled shield lichen, is a species of foliose lichen in the family Parmeliaceae. It is found in the eastern United States and eastern Canada. The lichen was first formally described in 1962 by lichenologist William Culberson as a species of Parmelia. He collected the type specimen growing on tree bark in West Virginia, Hildur Krog transferred it to the newly circumscribed genus Punctelia in 1982.
Punctelia reddenda is a widely distributed species of foliose lichen in the family Parmeliaceae. It occurs in Africa, Europe, North America, and South America, where it grows on bark and on rock.
Punctelia negata is a little-known species of foliose lichen in the family Parmeliaceae. It is found in South America.
Punctelia riograndensis is a species of foliose lichen in the family Parmeliaceae. Found in Africa and South America, it was formally described as a new species by Norwegian lichenologist Bernt Lynge in 1914, as Parmelia riograndensis. The type specimen was collected in 1892 from Porto Alegre Municipality in Rio Grande do Sul State (Brazil) by Swedish lichenologist Gustav Malme. In 1982, Hildur Krog circumscribed the genus Punctelia to contain Parmelia species with rounded pseudocyphellae, and P. riograndensis was one of the 22 species that she transferred to the new genus.
Punctelia subalbicans is a species of foliose lichen in the family Parmeliaceae. It is found in Australia and New Zealand, where it grows on the bark of various tree species.
Punctelia subpraesignis is a species of foliose lichen in the family Parmeliaceae. It occurs in Mexico, South America, and East Africa, where it grows on bark and on rocks. Major characteristics of the lichen that distinguish it from other Punctelia species include the C+ and KC+ rose spot tests of the medulla, ascospores that are smaller than 20 μm, and unciform (hooklike) conidia.
Punctelia cedrosensis is a species of foliose lichen in the family Parmeliaceae. It is endemic to Mexico, where it grows on the bark of conifers.
Punctelia punctilla is a species of foliose lichen in the family Parmeliaceae. It is found in Africa, South America, and North America, where it grows on bark and on rocks. The main characteristics that distinguish Punctelia punctilla from other species of Punctelia are the presence of isidia on the thallus surface, a pale brown thallus undersurface, and the presence of lecanoric acid in the medulla.
Punctelia hypoleucites, commonly known as the southwestern speckled shield lichen, is a species of foliose (leafy) lichen in the family Parmeliaceae. First formally described by Finnish botanist William Nylander as a species of Parmelia, it was transferred to the genus Punctelia in 1982. The lichen is found in Africa, North America, and South America, where it grows on the bark of both hardwood and coniferous trees. Its greenish-grey thallus is covered with tiny white pseudocyphellae – minute holes in the thallus surface that facilitate gas exchange. Some macroscopic features that help distinguish this species from other related members of the genus include the presence and the structure of the apothecia, the absence of asexual surface propagules, and the light brown color of the thallus undersurface. Chemically, the presence of lecanoric acid in the medulla and atranorin in the cortex help distinguish it from lookalikes.
Punctelia bolliana, the eastern speckled shield lichen, is a species of foliose lichen in the family Parmeliaceae. It is found in North America, with a distribution extending from the Canadian province of Ontario south to the central and northeastern United States and Mexico. It grows on the bark of both deciduous trees and coniferous trees. The combination of characteristics that distinguishes this species from others in genus Punctelia are the absence of the vegetative propagules isidia and soralia, a pale brown lower thallus surface, and the presence of the secondary chemical protolichesterinic acid in the medulla.
Punctelia perreticulata is a widely distributed species of foliose lichen in the family Parmeliaceae. It occurs in Mediterranean Europe and Russia, North America, South America, Australia, and New Zealand, where it grows on rocks, bark, or wood. Its main distinguishing features are its thallus surface, marked with many shallow depressions, grooves, or pits, and sorediate pseudocyphellae. The lower side of the thallus is ivory to tan towards the centre and the major secondary metabolite in the medulla is lecanoric acid. A lookalike species with which it has been historically confused is Punctelia subrudecta; this lichen can be distinguished from Punctelia perreticulata by the texture of the thallus surface, or, more reliably, by the length of its conidia.
Punctelia graminicola is a species of foliose (leafy) lichen in the family Parmeliaceae. It grows on rocks, and, less frequently, on bark in North America, South America, and East Africa. It has a blue-grey thallus measuring up to about 15 cm (6 in), covered with tiny pores called pseudocyphellae. Sometimes the lichen forms small lobes that project out from the surface. Fruiting bodies are uncommon in this species; if present, they resemble small cups with a brown internal disc measuring 3–10 mm (0.1–0.4 in) in diameter. A lookalike species, Punctelia hypoleucites, is not readily distinguishable from Punctelia graminicola by appearance or habitat alone; these species can only be reliably differentiated by examining the length of their conidia.
Parmelia ernstiae is a species of foliose lichen in the family Parmeliaceae. It occurs in Europe.
Punctelia subflava is a species of foliose lichen in the family Parmeliaceae that occurs in Australia.
Punctelia stictica is a species of foliose lichen in the family Parmeliaceae. It is widely distributed lichen, recorded in Africa, Europe, North America, South America, and Greenland. It is typically found growing on rocks.
Punctelia borreri is a species of foliose lichen in the family Parmeliaceae. It is a common and widely distributed species, occurring in tropical, subtropical, and temperate regions of Africa, Asia, Europe, North America, Oceania, and South America. The lichen typically grows on bark of deciduous trees, and less commonly on rock. Some European countries have reported increases in the geographic range or regional frequency of the lichen in recent decades, attributed alternatively to a reduction of atmospheric sulphur dioxide levels or an increase in temperatures resulting from climate change.
Parmelia barrenoae is a species of foliose lichen in the large family Parmeliaceae. It was formally described as a new species in 2005. Before this, it was lumped together as one of several lichens in the Parmelia sulcata group—a species complex of genetically distinct lookalikes. Parmelia barrenoae is widely distributed, occurring in Europe, western North America, Africa, and Asia.