Allographa pruinodisca
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| Allographa pruinodisca | |
|---|---|
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Graphidales |
| Family: | Graphidaceae |
| Genus: | Allographa |
| Species: | A. pruinodisca |
| Binomial name | |
| Allographa pruinodisca Aptroot (2022) | |
Allographa pruinodisca is a species of corticolous (bark-dwelling) crustose lichen in the family Graphidaceae.[1] It occurs in Brazil.
Allographa pruinodisca was formally described by the Dutch lichenologist André Aptroot. It was identified as a new species as part of a significant biodiversity assessment in a compact region of the Amazon rainforest. The species name, pruinodisca, is derived from the Latin words for "frosty" or "pruinose" (pruinosus) and "disc" (discus), referring to the distinctive pruinose (frosty-appearing) disc of its lirellae (long, slit-like reproductive structures).[2]
Description
The thallus of Allographa pruinodisca is crustose, continuous, and adheres closely to the surface of the tree bark. It has a dull, dirty pinkish-white appearance, extending up to 7 cm (2.8 in) in diameter and reaching a thickness of up to 0.1 mm. The photobiont, or photosynthetic partner, is trentepohlioid, a type of green algae.[2]
The species is recognised for its "striatula-morph" lirellae (fruiting bodies), which are linear yet wavy and often branched. These reproductive structures are up to 4 mm long and about 0.4–0.5 mm wide, with a nearly closed, thinly white pruinose disc. The excipulum (the outer layer surrounding the ascoma) is fully carbonised.[2]
Ascospores are hyaline (transparent), with 17–21 septa, measuring 80–90 by 9–12 μm, and arranged four per ascus. They are notable for their violet reaction to iodine (IKI+). Chemical analysis reveals no secondary metabolites in the thallus, which does not react to standard lichen spot tests (UV, C, K, KC, and P).[2]