How wonderful it is to have access to such deep observation... I have seen things that I could have never imagined because of this technology and these people. There is so much knowledge in the room... yesterday I was diverted from my microscope to learn about harvesting nettles and even more ways of storing and eating them: drying, teas, remedies, etc.
I found a lichen last month, only two days after the meeting. I was nettle hunting and harvesting if you will recall. I shared the context and where I found the lichen. It looks like a beast! It was scary and exciting... so I picked it from the top of a moss-covered stump and brought it with me to the Licheneers for some help.
I struggled mightily with the biology terms and vocabulary. I understand the basics of biology but it is not readily available in my mental database... so I re-learn high school science while jumping into a higher academic level... with folks who have been studying these things for years. They are kind to me as I ask the most rudimentary questions. But it is good for me to start anew and hopefully the answers they give are helpful to them as they explain the very basics.
Last night I identified this (not my picture) :
(copied on April 10, 2013 from: http://donegal-wildlife.blogspot.com/2012_02_01_archive.html)
After about an hour of using a dichotomous key, I came to the genus, PELTIGERA. I got there wrongly as it turns out, but I was right in the genus! It is a "Pelt" Lichen, a type of foliose (or leaf-like) lichen. Eventually, with the help of Fred Rhoades, our brave leader, I identified it down to the species.
It is called Peltigera membranacea. It has furry veins on the underside, and you can see the thalli are thin and like spikes almost. A thallus (pl: thalli) is a root-like structure, but not technically a root because it doesn't transport nutrients. They are likened (pun!) to holdfasts for kelp in the ocean. They simple keep the organism attached to a surface. I think this is correct but I might be wrong :)
This was the first of many more lichens I hope to study and identify. One characteristic and dozens of vocabulary words at a time! See you next second Tuesday.
Hi Dave: Just saw this post for the first time. Currently we are meeting on Thursdays. (For up-to-date info about meeting times please go to 'Google Groups" and type in the word Licheneers and you'll be able to see the posts of the most recent meetings. If you want to be added to the mailing list you can sign up as it is open to all! )
ReplyDeleteThe thallus of the lichen is actually the 'body' of the lichen and in most lichens consists of stratified layers. You can think of the thallus being like a peanut butter and jelly sandwich!! The 'bread'' layer is the 'cortex' or outer covering. Then there is a thin layer of the 'photobiont' which is the "food' producing part of the lichen that consists of green algae and/or cyanobactera (also called blue-green algae,) If you slice a lichen from the top part of it to the bottom you can often see this little layer of 'green' or 'dark' green of the photobiont. (Think of this as green jam!)
Then just below this is the white fungal filaments. In Usneas this forms into a white chord in the center of the lichen when you break it open. Then at the bottom you again most often have a cortex (like the outer layer of bread in a sandwich) only this often looks different from the top cortex. The little root-like structures you mentioned are called rhizines. They help the lichen grab on to the soil and moss. I think they are totally spikey-cool and Pelt lichens are one of my favs! Peltigeras are often found in low-light areas of the forest understory. Many of them (the ones that look gray when dry and olive/brownish colored when wet have cyano-bacteria in them. These lichens fix nitrogen into the soil and provide the growing forest with this essential nutrients to thrive!