Likin’ lichen

I am of the opinion that lichens are very interesting creatures. Consider that members of the group have existed for more than 400 million years, while conifers have been around a mere 250 million years and the flowering plants came on the scene a scant 150 million years ago. Lichens are even more ancient than mosses and ferns which are known from approximately 350 million years ago. Lichens live what can only be described as a tenuous life. Although some may be found in extreme environments such as tundra and desert, most live a quiet existence in more temperate environments, growing as epiphytes and covering the surfaces of trees, rocks, and soils. Lichens are unusual in that they represent the symbiotic union of an alga and a fungus. Algae are photosynthetic and are able to fix atmospheric carbon into sugars in support of themselves and of the fungal partner with which they live. For its part, the fungus provides protection for its algal symbionts and acts to take up water and mineral nutrients in support of algal growth and metabolism. Some lichens may be quite colorful, most are not however and may go unnoticed. Although inconspicuous, lichens are important ecological players in the process known as primary succession. Because they are able to live and thrive under very dry and nutrient-poor conditions they are some of the first organisms to colonize open substrate when it becomes available. Once lichens become established, their presence can modify harsh environmental conditions thereby facilitating the immigration of other sorts of colonizing species, and thus the sequence known as secondary succession may proceed apace. I also appreciate lichens because many act as indicators of environmental quality. They are living biomonitors much like the proverbial Canary in the Coal Mine. As it happens, lichens are particularly sensitive to sulfur dioxide and to acidified rain water. Different species show different tolerances to airborne pollutants so one can gauge air quality by a census of the lichen population in a particular area. And, finally, because lichens are adapted to live in nutrient-poor situations, they grow very slowly, perhaps just 0.1 – 10 mm per year. So, the next time you’re out for a stroll through the woods or for a hike up a hill, keep an eye out for these very pretty, very living, things and step aside.

lichen2

17 thoughts on “Likin’ lichen

  1. Pingback: New lichen species discovery in the Netherlands | Dear Kitty. Some blog

  2. Not sure what I like better, your photo, the prose or the title! All three are pretty fine! Thanks for the info on lichen. I’ve certainly seen it before but never gave it much thought. Amazing to think it’s been around for so long. The entire composition is very appealing! I always enjoy how you manage to capture so much texture!

  3. Definitely one of my favorite life forms. Thanks for the beautiful photo of a Pennsylvania lichen 🙂 We’ve only got a handful of foliose lichens here in the Mojave … mostly just little crustose beauties.

    • Hey … there you are! What a delight! I wonder why you are showing as ‘anonymous’? In any event … wasn’t your paper about lichens? Or was it fungi? I’m getting old … can’t remember! How are you folks doing? We’ve been cold … hay supply is low and wood is getting down there. I think we’re going to have to restock on the former and are hoping that the latter will hold. Keep your fingers crossed. It is 5 degrees out right now and 75 in the kitchen, next to the stove – talk about contrasts. Anyway J says ‘Hi.’ Say the same to J from us. D

  4. That’s a great coincidence – another blogger I follow has recently posted stunning images of lichen, too … with the intention to document how beautiful they actually are if you look closely. I am also fascinated by these life forms that are not as spectacular at first sight but which are so resilient. It is absolutely awe inspiring that they have been around for hundreds of millions of years. I was not aware of the “symbiotic union” (it sounds a bit geeky – I always have to think of Star Trek DeepSpace 9 when reading about symbionts) – so now I know and I am even more impressed.

  5. I have the impression that plenty of nature photographers are attracted to lichens for their shapes and colors; I certainly am. Fortunately lichens are widespread (literally and figuratively) in wooded parts of Austin, so I don’t have to go far to find some.

  6. Great title 🙂 As we have so much exposed rock, and decent air quality, they abound where I live too. One variety, boreal felt lichen (Erioderma pedicellatum), was once widespread and is now virtually wiped out, except for a reasonably healthy population that still exists in Newfoundland.

  7. I agree! Lichens are fascinating! They are also very difficult to identify, which is part of the fun, of course. Allen, of the blog New Hampshire Gardner, is a pro. He finds and identifies all kinds of wonderful lichens where he lives. This is a wonderful photograph. I love the texture and color.

  8. So pretty. It looks like coral. I’m impressed that you know so much about these things and that you have an appreciation of all things great and small.

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