Gyalolechia fruticum, a new epiphytic species with a Mediterranean-Macaronesian distribution, is described. It differs in molecular data and in ecology from two closely related calcicolous species, G. luteococcinea and G. marmorata, both formerly called Caloplaca subochracea auct. The new species grows on coastal shrubs (rarely on wood), accompanied by species-rich communities of maritime epiphytic lichens. The typical habitat is undisturbed sand dunes, under dry conditions with frequent spells of humid air from the sea. The species is so far known from Greece, Italy, Tunisia, the Canary Islands and probably mainland Spain. We consider this conspicuous lichen an umbrella species of endangered and declining epiphytic communities of ancient shrub vegetation on well-developed sand dunes along Mediterranean coasts affected by touristic overexploitation.

Two new species, Placomaronea fruticosa and P. placoidea, are described. They were originally discovered in the southern Peruvian Andes at altitudes between 3000 and 4650 m. One specimen of P. fruticosa was subsequently also found among herbarium material collected in Argentina. Placomaronea fruticosa is terricolous in high altitude grasslands with rocky cliffs. It is characterized by its fruticose to subfruticose thallus, which is up to 8 mm tall and partially immersed in the substrate, its branches are bright to deep yellow, flattened and on the substrate surface their elongated apices resemble placodioid lobes of crustose species in the genus Candelina, whereas the cylindrical basal parts are pale beige to deep violet and mostly grow immersed in their substrate. The species has asci with over 20 ascospores in a 60–80 μm tall hymenium. Placomaronea placoidea is a saxicolous species, growing in rocky exposed areas. It is characterized by its tightly adnate, foliose, placodioid thallus with a bright to deep yellow upper surface. No fertile specimens were found. Both species newly described here are morphologically very similar to species of Candelina but are clearly distinguished by a cortex anatomy characteristic of Placomaronea. Cortex anatomy can thus be immensely useful to distinguish crustose and subfoliose genera in Candelariaceae, whereas secondary chemistry is shown to be quite uniform, with some chemotype variation of little taxonomic relevance. An updated ITS-only phylogeny of Candelariaceae is presented and compared with earlier phylogenies of the family. Several well-supported clades are identified, including Candelina, Placomaronea and Protocandelariella, but much of Candelaria and Candelariella s. lat. remain unresolved, and the relationships between the supported clades are not yet known. The limitations of currently available molecular data, primarily only ITS, are discussed, particularly in relation to the lack of support at species level, such as the two newly described species of Placomaronea. An updated key to currently accepted genera in Candelariaceae and all species of Placomaronea now known is provided.

A Spanish version of this abstract is provided in Supplementary Material File S1 (available online).

Chaenothecopsis inconspicua is a new anamorphic lichenicolous fungus forming black sporodochia on the thallus of Lecanora expallens. Molecular analysis demonstrates that the new species is positioned in the Mycocaliciales. Although a remarkable diversity of anamorphs was already recognized in Mycocaliciales, it is the first species within this order known to produce sporodochioid conidiomata. Chaenothecopsis inconspicua is currently known from several localities in the northern half of the Netherlands, most often on old Quercus robur trees in villages. A key to the lichenicolous fungi inhabiting Lecanora expallens is provided.

Dolichousnea longissima is famous as the world’s longest lichen, which typically reproduces asexually. Factors impacting its length and reproductive strategies are of theoretical interest and important for conservation. We discovered a Dolichousnea population with apotheciate thalli in Western China. Phylogenetic analyses using ITS sequence data confirmed specimens were D. longissima. Multiple phylogenetic branches included both apotheciate and non-apotheciate thalli, thus genetic differences within the ITS region were not related to apothecia production. There was no indication that apotheciate Dolichousnea specimens from this region belong to a separate, morphologically and genetically distinct population. In a field experiment, we transplanted non-apotheciate thallus strands of 10, 20, 40 or 80 cm length from higher to lower elevations: c. 4000 to 3400 m. Elevational gradients in temperature, relative humidity and vapour pressure deficit simulated future climatic change. We tested hypotheses regarding the impact of climatic stressors on D. longissima growth and reproduction. After three years of growth, thallus mortality was highest at the lowest sites. Of surviving thalli, 23% had fragmented, with fragmentation rates increasing with length. Other thalli thrived, reaching a maximum main stem length of 321 cm, with a maximum total length of 764 cm. Intact thalli showed negative length-dependent growth. Lower elevations were associated with initiation of sexual reproduction, reduced relative thallus length growth rates (RTLGR) and lower photobiont abundance, with apparent shifts of photobionts from the main stem to fibrils and reallocation of resources from length to central cord and fibril mass. Probability of switching to sexual reproduction increased with thallus length, but shorter thalli made greater relative investment in apothecia production. Detrimental impacts of climate change could reduce D. longissima range and biomass production, thereby also decreasing food availability for the endangered lichenivorous monkey, Rhinopithecus bieti. Conservation efforts should be prioritized at sites currently hosting abundant, fast-growing thalli, and high-elevation mature forests where D. longissima is most likely to persist under future climatic change. Apotheciate populations need protection because sexual reproduction theoretically generates genetic variability, increasing the likelihood of generating mycobiont genotypes adapted to altered climatic conditions.