Endocarpon riparium
Endocarpon riparium is a species of corticolous squamulose lichen in the family Verrucariaceae. This lichen was discovered growing near rivers in the Brazilian Amazon, where it forms patches on wood, tree bark, and rocks that are sometimes underwater. It reproduces by producing small detachable pieces along its edges rather than through typical spore-bearing structures, making it unusual among related species.
Taxonomy
Endocarpon riparium was described as new to science in 2016 by André Aptroot and Marcela da Silva Cáceres from material collected in the Amapá National Forest. The holotype was gathered near the field station at about 30 m elevation, on wood in disturbed forest; paratypes came from nearby primary tall forest on tree bark and on siliceous rock. The specific epithet refers to its riparian habitat. The authors placed the species in Endocarpon based on the structure, even though no ascomata were found, and noted that it is the first Endocarpon species described with obvious asexual propagules.
Description
The thallus consists of dense, adglutinated flat that do not overlap and together form rather indeterminate patches. It is corticate, smooth, somewhat shiny, and olive green, without a distinct. Some margins appear reddish, probably from iron incrustation derived from the substrate or river water. Squamules are about 50–80 μm thick with a 15–25 μm cortex. The consists of small cells. The lower surface bears branched, hyaline about 3 μm thick. Margins and cracks are lined with numerous minute dorsiventral of thallus tissue that detach easily and act as vegetative propagules. Ascomata and pycnidia were not observed. Endocarpon riparium is unreactive with standard spot tests; thin-layer chromatography detected no lichen substances.
Habitat and distribution
Endocarpon riparium grows on wood, tree bark, and siliceous rock close to rivers; some collections came from bark that is occasionally submerged. Collections have been made in both disturbed forest and primary tall forest. It is known only from Amapá state in Brazil, where it appears locally common along rivers.