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05 Jun 2018 106 views
 
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photoblog image Cap Stones

Cap Stones

Xanthoria parietinais is a common lichen here and most everywhere. The stump is left specifically for Larry.

 

 

photoblog image stone 4 2018.jpg

Cap Stones

Xanthoria parietinais is a common lichen here and most everywhere. The stump is left specifically for Larry.

 

 

photoblog image stone 4 2018.jpg

comments (15)

LOL! Thanks for the shout-out, Mary. smile
Mary MacADNski: It was an interesting stump with an additional saw mark. I thought you'd like it.
  • sherri
  • Little Rock, Arkansas, USA
  • 5 Jun 2018, 02:22
the lichen in our area is a soft green

while i like it on rocks and stones in my gardens, it truly ruins grave markers and sometimes covers the names and/or dates

a unique shape
Mary MacADNski: There are plenty of lichens and mosses, with soft green common in both.
I do like Lichens, they can be so colourful.
Mary MacADNski: This yellow one is very colourful.
It is lovely... and makes a great post along with the capstones! The one on it's side is of interest...
Mary MacADNski: There were some on the ground too. It was an interesting cemetery.
  • Philine
  • Germany
  • 5 Jun 2018, 05:38
The Cap stones are very interesting -what is their function? (sorry, my stupid question)
Mary MacADNski: Most elements of stone monuments are surely decorative.
  • Chris
  • Not Nowhere
  • 5 Jun 2018, 06:36
Larry'll love 'em
Mary MacADNski: The stump was like one he just showed, with an extra saw mark.
  • Alan
  • Great Britain (UK)
  • 5 Jun 2018, 07:47
I like the growth on the stone.
Mary MacADNski: The yellow is very bright.
  • Alan
  • Great Britain (UK)
  • 5 Jun 2018, 07:48
... a fine collection of cap stones in your other image.
Mary MacADNski: There were others too.
  • gutteridge
  • Somewhere in deep space
  • 5 Jun 2018, 07:52
Someone once told me that good lichen is a sign of quality air.
Mary MacADNski: That is the case with certain lichens.
Beautiful color contrast on the stone.
Mary MacADNski: Yes, the two lichens look good with that grey.
I wonder if the sea air encourages this type of lichen, Mary.
Mary MacADNski: I don't think so because they were plentiful where I grew up.
I really like all these photos Mary, especially the lower quartet, or is that quintet.
Mary MacADNski: I like that one too. The bleached cap looks so incongruous.
  • Anne
  • United Kingdom
  • 5 Jun 2018, 14:43
A great indicator species.
Mary MacADNski: A most plentiful species.
Lichens are made up of two or more closely interacting organisms, a fungus, and one or more partners, called photobionts. The photobiont may be an alga and/or cyanobacteria, both of which can produce simple sugars by photosynthesis. In contrast, fungi are 'heterotrophic' and require an external source of food. The fungi build the structure of the lichen thallus, within which they provide conditions for a long term, stable association with their photobionts, the basis of the lichen symbiosis.

There is some debate about the exact nature of the symbiotic association between the lichen-fungi and their photobionts. Are the fungi ‘farming’ the photobionts in a controlled parasitism, or are the photobionts gaining some benefit also? There is good evidence for the lichen symbiosis as a mutualism, in which both partners benefit from the relationship. It is clear that fungi obtain their carbon-source in the form of simple sugars, but the photobionts seem also to be provided with optimal living conditions, in which their populations are often much larger than outside lichens. The photobiont probably also benefits from improved access to mineral nutrients which are provided because of fungal digestion outside their cells. Last, but not least, the interior of lichens is often a place richly infused with complex secondary fungal chemicals found nowhere else in nature, and these compounds are likely to play a role in protection from UV radiation, desiccation, and grazing by herbivores as well.

However, there are also good arguments in favour of the controlled parasitism camp. Up to half of the carbon fixed by algae is immediately converted to fungal sugars which are inaccessible to the alga itself. Secondly, some lichens which can form stable associations with their ‘usual’ host algae, form parasitic-type interactions with non-host algae when grown in the lab. In fact, it is thought that many early stages of developing lichen spores may survive using such a parasitic or saprophytic strategy. Lastly, there are many lineages of lichen fungi that are parasitic on other lichens – the so-called lichenicolous lichens! In some cases, non-lichen fungi have evolved from lichenised forms. These can be specialised opportunistic parasites or saprophytes or even symbionts, competing for nutrients with other fungi in the lichen thallus.

The symbiosis may be more complex than this. Recent work by Spribille et al has found yeasts embedded in the cortex of ascomycete macrolichens, and their abundance correlates with previously unexplained variations in phenotype. There is also convincing evidence for a consistent presence of non-photosynthetic bacteria within the thalli of all lichens, although the role of these bacteria is as yet unknown. Interestingly, a role for non-photosynthetic bacteria was suspected for many years, as the relichenization of separately cultured fungi and algae in the lab was facilitated by the presence of bacteria.
Mary MacADNski: I see!
A lovely orange lichen!

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for this photo I'm in a constructive critical comments icon ShMood©
camera Canon EOS REBEL T3
exposure mode aperture priority
shutterspeed 1/2000s
aperture f/5.0
sensitivity ISO100
focal length 170.0mm
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