Saxiloba: a new genus of placodioid lichens from the Caribbean and Hawaii shakes up the Porinaceae tree (lichenized Ascomycota: Gyalectales)

The new genus Saxiloba is described with the two species S. firmula from the Caribbean and S. hawaiiensis from Hawaii. Saxiloba is characterized by a unique, placodioid thallus forming distinct lobes, growing on rock in shaded to exposed situations with a trentepohlioid photobiont and a fenestrate thallus anatomy with distinct surface lines. The material is often sterile, but Porina-like perithecia and ascospores had previously been described for the Caribbean taxon and were here confirmed for both species. Molecular sequence data also confirmed placement of this lineage in Porinaceae. Its position within that family supports the notion that Porinaceae should be subdivided into a larger number of genera than proposed in previous classification attempts. Compared to other Porinaceae, Saxiloba exhibits a unique morphology and anatomy that recalls taxa in the related family Graphidaceae and it substantially expands the known phenotypic variation within Porinaceae. The two recognized species are similar in overall morphology but, apart from their disjunct distribution and different substrate ecology, differ in lobe configuration, color and disposition of the crystal clusters and resulting surface patterns.

Thallus anatomy of Canoparmelia texana (Parmeliaceae, lichenized Ascomycota)

Conventional techniques for structural studies under light microscope and scanning electron microscope were employed to describe the histology of thallus in Canoparmelia texana, a lichen with wide distribution in open environments and fairly common in the cerrados and urban areas of Brazil. This study describes a new type of cortical organization for the family Parmeliaceae, in C. texana the upper cortex is lacunar, showing a large quantity of small intercellular spaces or lacunae. The anatomical features including medulla thickness, hyphal orientation pattern, rhizines thickness and crystals inclusions have an important adaptive role for the success of C. texana in Brazilian cerrado, a savanna-like ecosystem.

Comparative thallus anatomy of two Parmotrema (Parmeliaceae, lichenized Ascomycetes) with reticulate maculae

Using conventional techniques for structural studies under conventional microscopy, polarizing light microscopy and scanning electron microscopy this work describes and compares the thallus anatomy of two Parmotrema species with reticulate maculae, previously included in the genus Rimelia: Parmotrema cetratum (Ach.) Hale and P. clavuliferum (Räsänen) Streimann. The data showed that the species are anatomically similar, including the presence of epicortex, the upper cortex anatomy and the characteristics of rhizines and ciliae. In the medulla of the two species there are star-shaped clusters of hyphae associated with the presence of salazinic acid. This study showed that the anatomical characteristics are constant for the Parmotrema group studied.

Krogia coralloides, a new lichen genus and species from Mauritius

The new corticolous lichen genus Krogia and species K. coralloidesare described from humid forest in Mauritius. The genus shows affinities with Phyllopsora, but differs in characters of the ascus, ascospores, and thallus anatomy. The ascal characters make its inclusion in the Bacidiaceae or Phyllopsoraceae problematic. The lichen contains boninic acid and an apparently related compound.

Labyrintha Implexa (Porpidiaceae), a New Genus and Species from New Zealand

Labyrintha Malcolm, Elix & Owe-Larsson, a new genus in the Porpidiaceae, is described. It is based on the crustose taxon L. implexa Malcolm, Elix & Owe-Larsson, a saxicolous species from acidic rocks in alpine and subalpine areas in New Zealand. Labyrintha is distinguished from closely related genera by a combination of characters: cephalodia, immersed apothecia, large, simple ascospores (60–70 × 30–35 μm), halonate when young and dark-pigmented when mature, fusiform conidia, no cortex, no thallus chemistry, densely packed anticlinal hyphae, and a previously undescribed thallus anatomy in which the photobiont is arranged in anastomosing vertical sheets.