Thursday 17 March 2016

Lepraria incana - Dust Lichen

 Learn your Lichens 8

Learn your Lichens Series
1. Arthonia radiata
6. Lecanora gangaleoides
7. Physcia tenella
8. Lepraria incana

The word "Dust" is useful for describing the genus Lepraria. The lichens have no structure and a closer close up reveals... Dust.
Well, fluffy granules.

Leparia means "Scurvy"
incana means "White, hoary"

Our Townhead area of Settle gave yet another lichen to this website series.. On Wednesday Ilona Warham said "Come and see this lichen - it grows in deep shade in crevices in our garden wall - yet it can look ever so bright"

It can sometimes be seen in the distance growing in big very pale blue green -white patches patches on the shady side on mossy tree trunks...  I need to find some pics near Settle..

I took a photo of the  south west facing wall at the edge of their garden. It was built into the hillside 30 or 40 years ago - so the lichens must have grown since then. Ignore Arrows 3, and 4 - Concentrate on the ledge just below arrow 1

The Lepraria incana has been increasing on this wall over the past few years, I was told. 

The Lepraria is bluish greyish green and is growing on the moss and in the crevices

Arrow 2 points to this crevice

When I put my camera close and used the flash you can see there is lots of Lepraria inside.

Lepraria incana in white under UV light.

It is very tolerant to sulphur dioxide pollution.

I first learnt about Lepraria incana when teaching at Malham Tarn in 1979 . The frame of the old coalhouse door at the Field Centre is made of sandstone, whereas the rest of the wall is Limestone. Oliver Gilbert describes it in his paper in 1963 on Malham Tarn House.

The pale powdery Lepraria grows on the sandstone, whereas the bright orange alga Trentepohlia grows on the limestone -- but there is overlap. Click on the article from the paper about Malham Tarn House - Its architecture and lichens by Raistrick and Gilbert in 1963

The wall faces north so is shaded all day, and it is the coal house so the wall is not heated by the building.

We are looking at the wall near the coalhouse in this picture here - the coal house is just off to the right, but you can see a white patch on the gatepost  wall which is Lepraria. (I think - need to go up and double check) - Then I'll photo the "coal house door" too. It looks fairly similar, thoough the wall was drastically repaired/repointed/plants removed 10-20 years ago.

Other plants with the name incana:

Alnus incana - grey alder
Matthiola incana - Hoary stock
Draba incana - Hoary Whitlowgrass or Twisted Whitlowgrass - a rare white crucifer that is found in our area (limestone/mountains)

Thursday 10 March 2016

Beginners Workshop: Top Twenty Lichens of Horton in Ribblesdale Churchyard

Here is the report of the beginners workshop held on 2 April.. (The advert is lower down)

The forecast said rain but sort of clearing up. Only it didn't clear up.

I had four takers for the workshop. A big thank you to Melanie, Sue, Pauline and Penny for coming.

And a thank you to the church people for letting us use the church.

We set ourselves up at the back of the church round a table which worked well.

We went outside and as a short "pre-introduction" found examples of Leprose (Dusty) Crustose (Crusty) and Foliose (Leafy.. Lusty?) Lichens -  (Lepraria incana - in the shelter and still looking like dust) Lepraria nivalis- though rather soggy  - as Leprose;  Rhizocarpon geographicum as Crustose and Parmelia saxatilis as Foliose.

We came in and had cups of tea and biscuits (thanks Pauline).  We looked at examples of lichens I had brought in with me and talked about the structure of lichens. A visiting cyclist took a photo of us.
See we are happy.

Then we went for a walk round the churchyard using the lichens trail. Still lightly raining. But better for looking at lichens than glaring sunlight or snow or frost.

After the Nostoc (Spittle of the Moon) and Collema (Black Jelly-Lichen) we came back inside, had coffee, did star jumps, and settled down to looking at structure in more detail.

At 12.30 we went outside and concluded the trail, finishing at the overhanging ash tree with its Xanthoria parietina and Parmeina pastillifera,   and then seeing some Protoblastenia rupestris at the porch entrance, next to the Caloplaca flavescens.

On the way back to Settle we made a slight detour towards Wharf to see  Rhizocarpon geographicum in situ.

Lower on the wall was some Porpidia macrocarpa.

Porpidia macrocarpa


All welcome at the Beginners Lichens workshop 2 April: Horton in Ribblesdale. 10am-12.30pm
For details and to book contact  Judith Allinson - Cost: £15 (Children £3.00) - Concessions available.

Learn a little about this fascinating topic - then amaze your friends!

We will spend a period indoors learning about the structure of lichens, have a cup of tea, and then have a walk around the churchyard. We will use the "Guide to the Top Twenty Lichens in Horton churchyard" prepared by Judith, and participants will keep a copy of the guide. Hand lenses will be provided. Please bring warm clothes at this time of year.

People who have attended on previous years will be encouraged to test out the draft 2016 leaflet: The next top twenty lichens: (i.e. Lichens 21 to 40) ...

Here are the Display boards I prepared for the  2015 Event

If you would
Your life enrichen,
Then study Lichen
If you prefer
Hikin' and bikin,
Then study Lichen

Both pronunciations are correct - but most people say the latter - liken.

Here's Horton in Ribblesdale churchyard, on a sunny day..

Lichen number 1 is on the porch wall. 

Can you see it here? The bright orange one.
I decided to call it "Limestone orange lichen"
 in the absence of any other English name

Its Latin name is Caloplaca flavescens.
It is a crustose lichen. The edge of the lichen has narrow, pleated lobes
and this feature is referred to as "placodioid". (Click on the picture to see a larger picture

You'll recognise it again at the stile at the east.

These pictures were taken at a similar event at Horton in autumn 2014

Here we are looking at the boundary wall in the north.
You can see we are holding the
"Guide to the Top Twenty lichens of Horton churchyard"
 that I had prepared

The display 

I am happy to organise Beginners Lichens workshops at Ingleton and Grinton Churchyards and 
Beginners Mosses Workshops at Ingleton, Giggleswick and Chapel le Dale if a group would like to "book" me.

See more posts on Lichens  on this website here