Field of Science

Real tough guys - lichens

Having dodged the worst parts of an ice storm, a few days of warmer weather are predicted where the daytime temps will be above freezing. Along with this comes rain, but with the ground still frozen, a lot of runoff is expected.  Here and there a few sprouts of early bulbs are peeking out.  However if you want to see some happily green organisms, start looking at tree bark and branches.  Without the crown of leaves, more sunlight will fall on tree trunks than you might expect, and lichens take advantage of this. These are really tough organisms. Tree bark, stones, cement, these are really hard substrates; organisms growing there are highly exposed, subject to desiccation and temperature extremes, and yet in places the lichens are almost luxuriant.  Locally common lichens grow as a crust and so don't look as lush as the larger, more branched or leafier types (fruticose or foliose).  Although TPP is not adept at identifying lichens, he loves the Lichens of North America; a wonderfully illustrated atlas of lichens (just the ID keys and other field guides are also available).  Should you decide to give it a go, you'll run into a bit of a terminological learning curve and the need of come magnification.  Maybe a kind reader will offer some suggestions about the lichens shown here.
If you don't already know this, lichens are symbiotic organisms, basically a fungal body housing symbiotic algae. The algae can still be free-living, and so to the fungus, but neither one alone looks like the lichen.

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