Heidi Burdett · @HLBurdett
178 followers · 100 posts · Server mstdn.science
Stephen · @lichens
23 followers · 15 posts · Server flipping.rocks

My final image of the immersed thallus of Opegrapha saxatilis(?) nicely combining 250 million year old quartz crystals with modern lichen hyphae exploiting pore space and fractures!

#lichens #crustose #endolithic

Last updated 2 years ago

Stephen · @lichens
23 followers · 15 posts · Server flipping.rocks

My final image of the immersed thallus of Opegrapha saxatilis(?) nicely combining 250 million year old quartz crystals with modern lichen hyphae exploiting pore space and fractures!

#lichens #crustose #endothithic

Last updated 2 years ago

Stephen · @lichens
23 followers · 14 posts · Server flipping.rocks

apothecia This is hard to describe - from macro to micro. A lirellate crustose lichen (probably Opegrapha calcarea group - O. saxatilis(?)) grows abundantly on this exposed sandstone coastal outcrop. The sandstone is porous and friable. First image shows the nature of the substrate, regularly dosed with seawater spray. Second image shows details of the black lirellate apothecia on the RHS with the white thallus exposed in the centre - from a distance these lichens appear whitish on the red sandstone. Third image shows how apothecia appear to grow around individual grains, i.e. along grain boundaries. As the lichen matures the apothecia appear to fill remaining areas. Fourth image is a cut through the rock (ie a cross section through the substrate below the apothecia) showing the endolithic nature of the thallus as the hyphae fill the cracks and pores of the rock. The dark part at the top of the image is the non-illuminated surface. Scale bar 1000microns.

#lichens #crustose #lirellae

Last updated 2 years ago

Stephen · @lichens
14 followers · 10 posts · Server flipping.rocks

Lichens are good indicators of pollution from the air or water. However, some species have adapted to growing in poor air conditions and in areas of heavy metals. This image shows the effect of rain water running down a galvanised fence and dripping onto this rich assemblage of crustose lichens. The small amount of zinc dissolved from the contact with the fence has killed all but a few lichens, as shown by the bare patch. A healthy and fertile Stereocaulon is thriving just out of the splash zone in the upper RHS. This phenomenon is also recorded around the base of power pylons. Ironically many lichens thrive on an iron substrate - second photo shows Rhizocarpon geographicum and others growing on an iron stake.

#lichens #crustose

Last updated 2 years ago

Stephen · @lichens
4 followers · 4 posts · Server flipping.rocks

Rhizocarpon lecanorinum, a growing on Mesoproterozoic granite. The thallus comprises an outer open network of black hyphae - prothallus, with yellow (yellowy-green) areoles towards the centre. Fruting bodies - apothecia - are black and surrounded by the yellow areoles. This specimen is partially mature. These species are early colonisers on fine-medium grained rocks found on the edges of water and like to face the sun!

#crustose #lichen

Last updated 2 years ago