Niebla (lichen)

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Niebla
Niebla homalea
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Lecanorales
Family: Ramalinaceae
Genus: Niebla
Rundel & Bowler (1978)
Type species
Niebla homalea
(Ach.) Rundel & Bowler (1978)

Niebla is a

Mendocino County in California south to Baja California Sur.[2]

Taxonomy

The genus name is a substitute name

International Code of Botanical Nomenclature. Additionally, the type species name for Niebla is Niebla homalea, based on the name given to the one species that had been recognized by Montagne for the genus,[5] not Niebla ceruchis.[6]

The genus Niebla has also been interpreted broadly to include the genus

spot tests[7] of which the most useful in Niebla appears to be para-phenylenediamine (pd); the nine species in the narrow classification [2] that contain depsidones (pd+) are all placed under N. josecuervoi in the broad classification.[7] A second group that contains depsides but also includes the acid-deficient chemotype (N. homaleoides), collectively treats 32 species under the name N. homalea. The inclusion of the acid-deficient species in N. homalea disregards the chemotaxonomic attribute of a pigment associated with species that contain salazinic acid.[2] Both classifications recognize N. isidiaescens. Eleven other species that are treated in Vermilacinia [2]
are distinguished by thallus morphology.

monophyletic.[6] However, source material (voucher specimens) cited in the later study for the basis of the DNA analysis of Niebla was reported to be from California and identified N. homalea with protocetraric acid and triterpenes. But this chemotype had not been known in Niebla, nor are depsidones known to be present in N. homalea, nor are they present in any species of Niebla in California;[2] protocetraric acid is found only in N. pulchribarbara, which lacks triterpenes, a rare species that occurs in northern Baja California.[2] In the Lichen Flora of the Greater Sonoran Desert Region, the description given for N. homalea[7] erroneously described the species to have depsidones, including protocetraric acid, which may be confused with salazinic acid when conducting thin-layer chromatography. Salazinic acid is a common lichen substance accessory to triterpenes in species of Vermilacinia, while it may also be noted that the morphology of V. laevigata is easily confused with that of N. homalea.[2]

In view of the controversial classification of this Ramalina complex of genera, and that many of the species are common along the Pacific coast of North America, it may be helpful to conservationists to have molecular studies be conducted to correlate the different views of the species concepts with their DNA, which should include representative specimens from the entire geographic range of the species before drawing definitive conclusions about their synonymy.

Description

Niebla has 42 species distinguished by

secondary metabolites (lichen substances) and by morphology.[2] Niebla lichen substances fall into two groups. One group has triterpenes, the other lacks triterpenes. Species of Niebla that contain triterpenes also contain depsides as major lichen substances, which in a species may be either divaricatic acid or sekikaic acid.[2] The group lacking triterpenes contains depsidones as major lichen substances—protocetraric acid, hyprotocetraric acid, salazinic acid, or none of the acids are present in N. homaleoides. Usnic acid, pigments, and other unknown secondary substances are also produced but have little taxonomic value except for one pigment associated with species that produce salazinic acid. The same pigment occurs in the acid-deficient N. homaleoides.[2]

The morphological characters employed to distinguish species of Niebla include the orientation of ridges in the

isidia.[2] Most species occur in Baja California, Mexico.[2]

Niebla is related to Ramalina and Vermilacinia, distinguished from them by the presence of thread-like hyphae intertwined into gelatinized cords called chondroid strands. These strands run lengthwise within the central axis (medulla) of the Niebla thallus, and are visible to the naked eye when a branch of the thallus is sliced or torn. Chondroid strands also protrude into the cortical surface in various network arrangements in which species are recognized by their particular network structure.

Some Ramalina species in the

pseudocyphellae and more than one depside or depsidone accompanied by triterpenes and/or bourgeanic acid.[2] Their classification in Ramalina is supported by molecular phylogeny data.[6]

Vermilacinia differs from both Ramalina and Niebla by the absence of chrondroid strands, and by presence of other lichens substances, predominantly terpenes[2] that differ from those in Niebla. Of taxonomic significance is the diterpene (-)-16 α-hydroxykaurane, a rare secondary metabolite in lichens. This diterpene is found only in Vermilacinia within the Ramalinaceae, and also in Roccella (Roccellaceae).[10]

Species

The following lists all the species in the genus Niebla that have been recognized. In bold are those generally accepted. Listed separately are those also treated in the genus Vermilacinia. Species rare or isolated in occurrence are also noted.[2]

Species classified in Niebla also recognized in Vermilacinia

References

  1. ^ Brodo, I. M., S. D. Sharnoff, and S. Sharnoff. 2001. Lichens of North America. Yale University Press: New Haven.
  2. ^ a b c d e f g h i j k l m n o Spjut, R. W. 1996. Niebla and Vermilacinia (Ramalinaceae) from California and Baja California. Sida Miscellany 14, pp. 1-208. Botanical Research Institute of Texas, Inc., Fort Worth.
  3. ^ a b c Rundel, P.W. and P.A. Bowler, 1978. Niebla, a new generic name for Desmazieria (Ramalinaceae). Mycotaxon 6: 497–499
  4. ^ Montagne, D.M. 1852. Diagnoses phycologicae. Ann. Sci. Nat. Sr. 3, 18, 302–319.
  5. ^ Spjut, R. W. 1995. Vermilacinia (Ramalinaceae, Lecanorales), a new genus of lichens. In: Flechten Follmann; Contr. Lichen in honor of Gerhard Follmann; F. J. A. Daniels, M. Schulz & J. Peine, eds., Koeltz Scientific Books: Koenigstein, pp. 337–351.
  6. ^ a b c Sérusiaux, E., P. van den Boom, and D. Ertz. 2010. A two-gene phylogeny shows the lichen genus Niebla (Lecanorales) is endemic to the New World and does not occur in Macaronesia nor in the Mediterranean basin. Fungal Biology 114: 528–37.
  7. ^ a b c d Bowler, P. and J. Marsh. 2004. Niebla. ‘Lichen Flora of the Greater Sonoran Desert 2’: 368–380
  8. ^ "Lichens".
  9. ^ "Morphology of Lichens".
  10. ^ Culberson, C. L. 1969. Chemical and Botanical Guide to Lichen Products. Otto Koeltz Science Publishers: Koenigstein, p. 60
  11. ^ Sipman, H.J.M. 2011. New and notable species of Enterographa, Niebla, and Sclerophyton s. lat. from coastal Chile. Bibliotheca Lichenologica 106: 297-308.

External links

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