Biology:Candelina
Candelina is a small genus of lichen-forming fungi in the family Candelariaceae.[1][2] It comprises three species of yellow-colored, rock-dwelling crustose lichens. The lichens grow on sun-baked rocks in desert and semi-desert regions in the Americas and south-western Africa.
Taxonomy
Josef Poelt erected Candelina as a new genus in 1974 to segregate a small, anatomically distinct group of bright-yellow, [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], rock-dwelling lichens. He [[Glossary of lichen terms#{{biology:{1}}}|diagnosed]] the genus by its thin but bi-corticate, fragile [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] that are attached by [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] and lack rhizines and soredia; [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] apothecia; and eight, 1–2-celled, narrowly ellipsoid ascospores. He selected Placodium mexicanum (originally described by Maurice Bouly de Lesdain in 1914[3]) as the type species under the new combination Candelina mexicana, proposed a neoholotype for that species owing to the destruction of Bouly de Lesdain's herbarium, and at the same time recognized C. submexicana (as a new combination) and described C. africana as new. Poelt also stressed the genus's ecological coherence: species grow on non-calcareous, sun-exposed rock in seasonally hot, arid regions of the Americas and south-west Africa.[4]
Molecular phylogenetic analyses using DNA sequence data from the internal transcribed spacer regions recover Candelina as a well-supported monophyletic group within Candelariaceae, but relationships among the family's major lineages remain only partly resolved given the current gene sampling; recent workers caution against major generic rearrangements until broader multi-locus datasets are available.[5]
Description
The upper [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] of Candelina is distinctive: several layers of hyaline, clearly [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] cells are capped externally by a thick, dense band of yellow pigment [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]. Unlike the genus Placomaronea, there is no sloughing, colorless "coating"; the pigment layer sits directly on the [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], and the lower cortex is well developed where [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] meet the substrate. In keys to the family, Candelina is separated from Candelariella (which has a thinner, looser pigment layer and mostly [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] cortex) and from Placomaronea (which shows "peppered" pigment hoods on inflated apical cortex cells plus a fragile, hyaline outer residue). These anatomical differences are reliable even when gross thallus form is similar, and they are routinely used to avoid confusion with [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] Placomaronea species in the Andes.[5]
Chemically, members of Candelina share the family's rather uniform pulvinic acid-based profile. Thin-layer chromatography across multiple specimens recovered pulvinic acid with 4-hydroxypulvinic acid, sometimes accompanied by pulvinic dilacetone and calycin. spot tests on the thallus surface may be K+ (red), weakly reddish, or negative depending on concentration and combination of these metabolites. The chemistry is therefore of limited diagnostic value within the genus compared with cortex anatomy.[5]
Habitat and distribution
Candelina species are saxicolous lichens of warm, arid regions. Poelt described the genus as occurring on sun-exposed, non-calcareous rock, typically on horizontal to sloping faces, and emphasized that the group is characteristic of dry-warm areas in the Americas and south-western Africa.[4]
Within the Americas, Poelt placed Candelina submexicana in the south-western United States and Mexico, and Candelina mexicana from Texas south to Ecuador; he described Candelina africana from south-western Africa (fertile material then unknown). Together these records outline a disjunct range across seasonally hot, open sites on sunlit rock in the New World and south-western Africa.[4]
References
- ↑ "Candelina". Species 2000: Leiden, the Netherlands. https://www.catalogueoflife.org/data/taxon/3GRY.
- ↑ Wijayawardene, Nalin; Hyde, Kevin; Al-Ani, Laith Khalil Tawfeeq; Somayeh, Dolatabadi; Stadler, Marc; Haelewaters, Danny et al. (2020). "Outline of Fungi and fungus-like taxa". Mycosphere 11: 1060–1456. doi:10.5943/mycosphere/11/1/8.
- ↑ Bouly de Lesdain, M. (1914) (in fr). Lichens du Mexique (États de Puebla et du Michoacán) recueillis par le frère Arsène Brouard. pp. 1–31 [10]. doi:10.5962/bhl.title.79416. https://www.biodiversitylibrary.org/page/44219155.
- ↑ 4.0 4.1 4.2 Poelt, J. (1974). "Zur Kenntnis der Flechtenfamilie Candelariaceae" (in de). Phyton 16: 189–210. https://www.zobodat.at/pdf/PHY_16_1_4_0189-0210.pdf.
- ↑ 5.0 5.1 5.2 Ramos, Daniel; Hollinger, Jason; Bungartz, Frank (2025). "Two new species of Placomaronea (Candelariaceae: lichenized Ascomycota) in Peru, with a revision of secondary chemistry and cortical anatomy of Placomaronea, Candelina and Candelariella". The Lichenologist 57 (2): 61–81. doi:10.1017/S0024282925000040.
Wikidata ☰ Q5031658 entry
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